============================================================================== Claude Code session : 784d9092-d49c-4763-a56c-f60309f01b3d Project directory : /home/agent/TE_ting Started : 2026-07-19 08:46:04 Ended : 2026-07-19 09:23:17 User prompts : 4 Claude Code version : 2.1.215 ============================================================================== [2026-07-19 08:46:04] user: The Teenage Engineering EP-2350 is connected. It's REPL is available at /dev/ttyACM0. Right now it is running stock Micropython firmware. Your goal is to help investigate the remaining button pins. Read ./power_hold_findings.md for information about the device and how to keep it awake. That file documents GPIO19 as one of the handle buttons. Next we want to find the IO pins for the 3 side buttons, and the other handle button. There is one handle button that is pressed when the handle is all the way in (GPIO19), and another handle button that normally pressed when the handle is not held and gets released when user presses the handle. We don't know the IO pin of that button yet. Please devise tests to run with my help pressing buttons when appropriate to figure out which pins map to which buttons. [2026-07-19 08:46:07] agent: I'll start by reading the findings file. [2026-07-19 08:46:07] tool use: Read file_path: /home/agent/TE_ting/power_hold_findings.md [2026-07-19 08:46:07] tool result: Read 1 # EP-2350 power-latch / auto-sleep mechanism — SOLVED 2 3 Session date: 2026-07-19. Method: stock MicroPython v1.25.0 (RPI_PICO2) over the 4 raw REPL (`scratchpad/rp.py`), plus manual handle press/release testing by the 5 user. Static analysis of `ep-2350_firmware_1_0_8.uf2` was also done but the 6 answer came from live probing. 7 8 ## TL;DR 9 10 | Signal | GPIO | Sense | Status | 11 |--------|-----:|-------|--------| 12 | **POWER HOLD / latch control** | **GPIO2** | drive **HIGH** = stay powered, **LOW** = power off | **Confirmed** | 13 | **Handle switch sense** | **GPIO19** | **0 = handle pressed**, 1 = released | Confirmed | 14 | VBAT / VBUS / analog sense | GP25, GP26, GP28, GP29 | external pull-up / divider | Likely (see below) | 15 16 **There is no power-management chip on the I²C bus.** A scan under stock 17 MicroPython returns only `0x18` (accelerometer) and `0x1b` (NAU88L21 codec). 18 The power control is a discrete latch driven directly by **GPIO2**. 19 20 To keep the device alive under your own firmware, this is all you need: 21 22 ```python 23 from machine import Pin 24 hold = Pin(2, Pin.OUT, value=1) # assert before the handle is released 25 # ... and to power the unit off: 26 hold.value(0) 27 ``` 28 29 ## How the circuit behaves (observed) 30 31 1. **At power-on the latch is OFF.** The handle switch supplies power directly 32 while it is held. This is why stock MicroPython dies the instant the handle 33 is released — nothing ever asserts GPIO2. 34 2. **Driving GPIO2 HIGH sets the latch.** With GPIO2 high, releasing the handle 35 leaves the device fully powered and the USB REPL connected. 36 3. **The latch retains state when GPIO2 floats.** After setting the latch, all 37 GPIO output-enables were cleared (`GPIO_OE = 0x0`) and the device stayed 38 powered for minutes with the handle released. So GPIO2 is not a 39 continuously-refreshed "keep-alive" — it is a genuine set/reset latch (or a 40 push-button power-controller IC), not an RC/charge-pump hold. 41 4. **Driving GPIO2 LOW resets the latch → immediate power off.** USB drops 42 instantly. This is the firmware's shutdown path. 43 44 So the TE firmware's documented behaviour is pure software timing on top of this: 45 it watches GPIO19 for the handle release, runs its 5-minute power-save timer and 46 20-minute off timer, and then drives GPIO2 low to cut power. On USB it simply 47 never drives GPIO2 low. 48 49 ## Evidence chain 50 51 - **Shotgun test.** 19 plausible pins driven high + a 1 MHz square wave on GP16; 52 handle released → device stayed alive. Latch is in that set. 53 - **Invalid first bisection (recorded as a caution).** Progressively releasing 54 pins kept the device alive, which looked like a bisection but was not: the 55 latch was already *set* and simply retained. Any "does it stay alive" bisection 56 must power-cycle between trials. The corrected method drives pins **low** one 57 at a time within a single latched session. 58 - **Low sweep.** With the latch set and the handle released, candidates were 59 driven low one at a time: GP1 low → still alive; **GP2 low → device died.** 60 - **Clean confirmation.** Fresh power-on, `GPIO_OE = 0x4` (GP2 the *only* driven 61 pin, high), handle released → alive continuously for the full observation 62 window. 63 - **Cross-check with the TE firmware.** The read-only pin snapshot in 64 `pinmapping_findings.md` §4 shows GPIO2 as the **only pin driven HIGH** 65 (`2 PIO0 OE=1 IN=1`). At the time it was noted as unexplained; it is the 66 power hold. (TE drives it from PIO, but a plain SIO high works fine.) 67 - **Handle sense.** GP19 read 0 (hard-driven low, beating a 2 mA MCU drive) while 68 banded, and 1 after release, across several cycles. It is a switch to ground. 69 70 ## External-drive map of every GPIO (stock MicroPython, nothing else driving) 71 72 Only these pins have anything external attached; everything else floats: 73 74 ``` 75 GP14, GP15 external pull-up I2C1 SDA/SCL (codec + accelerometer) 76 GP19 driven LOW handle switch to GND (0 = pressed) 77 GP28 divider ADC2 — the only real analog sense line 78 GP29 tied to 3V3 ADC3 — hard-tied to the rail, not a sense line 79 GP20 driven LOW state-dependent, see caveat below 80 ``` 81 82 ### Analog sense lines — measured 2026-07-19 (USB powered, **no batteries fitted**) 83 84 Raw ADC, then each net loaded with the internal pulls (~50–80 kΩ) to measure its 85 source impedance. Loading is what separates a real divider from a floating pin: 86 87 ``` 88 pin float pull-up pull-dn swing verdict 89 GP26 1.365 V 3.101 V 0.105 V 2.996 V floating / unconnected 90 GP27 1.604 V 3.182 V 0.100 V 3.082 V floating / unconnected 91 GP28 1.630 V 1.755 V 1.500 V 0.255 V REAL DIVIDER, R_th ≈ 4.6 kΩ 92 GP29 3.290 V 3.290 V 3.288 V 0.002 V hard-tied to 3V3 rail 93 ``` 94 95 **GP28 is the only genuine analog sense line.** Its ratio against the measured 96 rail is `1.630 / 3.290 = 0.4954` — an almost exact **1:2 divider**, and 97 `R_th ≈ 4.6 kΩ ≈ 10k‖10k`. Both point to two equal resistors sensing the system 98 rail, i.e. **GP28 = VSYS/VBAT ÷ 2** (`get_vbat`). The competing reading — 99 VBUS ÷ 3.2 via 15k/6.8k, giving VBUS = 5.2 V — fits the impedance about as well 100 but requires an arbitrary ratio, so it is the weaker explanation. 101 102 **This is not yet decided.** The decisive test needs batteries fitted and USB 103 then unplugged: a VBUS sense collapses to ~0 V, a VSYS/VBAT sense holds at 104 ~1.5 V (3 V ÷ 2). That cannot be done with no batteries in the unit, because 105 unplugging USB removes all power. 106 107 `get_vbus` may well be a *digital* VBUS-present pin rather than an ADC channel; 108 no candidate identified yet. 109 110 #### One suggestive (not conclusive) data point 111 112 | condition | GP28 | GP29 (rail = ADC VREF) | 113 |---|---|---| 114 | USB only, **no batteries** | **1.630 V** | 3.290 V | 115 | USB + **batteries fitted** | **1.505 V** | 3.292 V | 116 117 GP28 moved by −7.7 % while the rail/VREF stayed put, so the change is real and 118 not a reference shift. A pure VBUS divider should not care whether batteries are 119 present, which **leans toward GP28 being a battery/VSYS sense**. `1.505 × 2 = 120 3.01 V` is a very plausible 2×AAA reading. 121 122 Treat this as suggestive only: between the two measurements the USB cable was 123 unplugged and replugged and may have landed on a different port, so a genuine 124 VBUS difference (5.2 V → 4.8 V) explains the same delta. Still unresolved. 125 126 ## Power-source behaviour (measured 2026-07-19) 127 128 - **Pulling USB powers the unit off**, even with the GP2 latch set *and* 129 batteries fitted. It does not fall back to battery power. This matches TE's 130 own documentation ("on usb power: the unit will stay powered until you pull 131 the cable"). The likely mechanism is that the power-path handover browns out 132 the RP2350, which resets GP2 and therefore clears the latch. 133 - **Plugging USB in does not power the unit on.** A powered-off unit does not 134 enumerate. Pressing the handle is the only way to *set* the latch. 135 - Consequence for testing: **GP28 can never be read with USB absent if the 136 session began on USB.** Any battery-only measurement must *start* from a 137 battery boot (see the session plan in `power_investigation_session1.md`). 138 139 ### ⚠️ Caveat: the digital probe is unreliable on floating pins 140 141 The pull-up/pull-down digital survey gave **different answers on different runs** 142 for GP20, GP25 and GP26 — an unconnected CMOS input just holds stray charge, so 143 it follows whichever pull was applied last and the timing changes the result. 144 Treat "floating" vs "external pull-up" from that method as provisional unless 145 corroborated. The ADC loading test above is definitive and overrides it for 146 GP26–29. GP25 (not ADC-capable) is therefore still uncertain, and GP20 read 147 externally-low on the second run only — possibly a second switch, or a line whose 148 state depends on whether the unit is running from the handle or from the latch. 149 150 ### ⚠️ Measuring inputs on this board: RP2350-E9 151 152 A naive "internal pull-up vs pull-down" probe reports **every** pin as externally 153 pulled high. That is the RP2350-E9 erratum: with the internal pull-down enabled, 154 a pad that has been high latches high. The reliable method (used above) is to 155 **drive the pin to the opposite state first to clear the latch**, then release it 156 to the internal pull and read: 157 158 - external pull-up test: drive LOW → release with internal pull-DOWN → reads 1 159 - external pull-down test: drive HIGH → release with internal pull-UP → reads 0 160 161 Also note **RP2350 SIO register offsets differ from RP2040**: 162 `GPIO_IN 0x004, GPIO_OUT 0x010, OUT_SET 0x018, OUT_CLR 0x020, OUT_XOR 0x028, 163 GPIO_OE 0x030, OE_SET 0x038, OE_CLR 0x040`. Using the RP2040 offsets silently 164 leaves pins driven. 165 166 ## What GPIO16 is *not* 167 168 GPIO16 is **not** part of the power mechanism — the device latches and holds with 169 GP16 completely idle. It is also **not** the codec MCLK (that is GPIO12, see 170 `nau88l21_pins.md`). Under TE firmware it is a driven, high-rate PIO clock output 171 with no external pull. Still unidentified. 172 173 ## Self-holding boot script 174 175 `scratchpad/device_main.py` is a `main.py` for stock MicroPython that asserts the 176 GP2 latch at boot (before anything else) and then logs GP28/GP26/GP29 plus the 177 whole `GPIO_IN` word from a background thread. Installing it and resetting was 178 verified working: after `machine.reset()` the device came back with 179 `GPIO_OE & 4 == 4` and `GPIO_OUT & 4 == 4`, i.e. it self-held with no 180 intervention. The latch-assert half of that script is reusable; the flash-logging 181 half is **not recommended** (see below). 182 183 ## ⚠️ Do not log to flash across a power-loss event 184 185 The GP28 battery test ended with the unit dropping into the **TING BOOT** 186 bootloader (`2367:0620`, mass storage, `INFO_UF2.TXT` → `UF2 Bootloader v1.0 / 187 Model: EP-2350`) instead of booting MicroPython. The logger was writing and 188 flushing `/plog.csv` every 500 ms precisely while power was being cut, which is a 189 good way to corrupt the littlefs filesystem or leave flash mid-write. 190 191 Both logging strategies tried this session failed, for opposite reasons: 192 193 - **RAM buffer** — erased by the power loss the test was designed to capture. 194 - **Flash file, flushed every 500 ms** — survives power loss in principle, but 195 writing *through* the power loss corrupted the device. 196 197 If a future session needs to capture data across a power transition, prefer: 198 sample into RAM, and **write to flash only once, after the transition, from a 199 still-powered device** — i.e. arrange for the device to survive (battery boot), 200 never for it to die mid-write. 201 202 ## Open questions / next steps 203 204 - **GP28: VBAT/VSYS vs VBUS.** The single unresolved question from this session. 205 See `power_investigation_session1.md` for a concrete, safer test plan. 206 - **`get_vbus`** — probably a digital VBUS-present pin; no candidate found. 207 - **GP25** — not ADC-capable, digital probe gave contradictory results across 208 runs, still unidentified. 209 - **GP20** — read externally-low on one run and floating on another. Possibly a 210 second switch, or a line whose state depends on handle-power vs latch-power. 211 - Whether the latch also has a hardware-only auto-off (the "20 min" figure is 212 firmware timing, but worth confirming it is not a hardware timeout). 213 - What GPIO16's clock drives (ruled out of the power path entirely). 214 [2026-07-19 08:46:08] tool use: Bash command: ls -la /home/agent/TE_ting/ description: List project files [2026-07-19 08:46:08] tool result: Bash total 13100 drwxrwxr-x 7 agent agent 4096 Jul 19 08:31 . drwx------ 15 agent agent 4096 Jul 19 08:45 .. -rw-rw-r-- 1 agent agent 9477 Jul 18 20:19 audio_codec_bringup_session1.md -rw-rw-r-- 1 agent agent 11274 Jul 18 21:24 audio_codec_bringup_session2.md -rw-rw-r-- 1 agent agent 7837 Jul 18 22:15 audio_codec_bringup_session3.md drwxrwxr-x 2 agent agent 4096 Jul 18 19:53 .claude -rw-rw-r-- 1 agent agent 2018007 Jul 17 13:44 DS_NAU88L21_DataSheet_EN_Rev2.8.pdf -rw-r--r-- 1 agent agent 1544192 Dec 4 2025 ep-2350_firmware_1_0_8.uf2 -rw-rw-r-- 1 agent agent 663879 Dec 4 2025 ep-2350_firmware_1_0_8.zip -rw-rw-r-- 1 agent agent 8334 Jul 17 17:57 firmware_testing_instructions.md -rw-r--r-- 1 agent agent 1136 Dec 4 2025 fw_download_readme.txt drwxrwxr-x 16 agent agent 4096 Jul 17 14:35 micropython -rw-rw-r-- 1 agent agent 10311 Jul 18 11:23 nau88l21_pins.md drwxrwxr-x 16 agent agent 4096 Jul 18 15:44 Nuvoton-ASoC -rw-rw-r-- 1 agent agent 12219 Jul 17 17:02 pinmapping_findings.md -rw-rw-r-- 1 agent agent 11158 Jul 17 16:11 pinmapping_plan.md -rw-rw-r-- 1 agent agent 11259 Jul 19 08:25 power_hold_findings.md -rw-rw-r-- 1 agent agent 8610 Jul 19 08:26 power_investigation_session1.md drwxrwxr-x 2 agent agent 4096 Jul 17 16:44 __pycache__ -rw-rw-r-- 1 agent agent 6411 Jul 17 15:38 rom_main.py -rw-rw-r-- 1 agent agent 11895 Jul 18 09:32 rom_readme.md -rw-rw-r-- 1 agent agent 7968417 Jul 17 13:52 RP-008373-DS-2-rp2350-datasheet.pdf -rw-rw-r-- 1 agent agent 648704 Jul 18 10:05 RPI_PICO2-20250415-v1.25.0.uf2 drwxrwxr-x 3 agent agent 4096 Jul 19 08:13 scratchpad -rw-rw-r-- 1 agent agent 2320 Jul 17 16:20 scratch_repl.py -rw-rw-r-- 1 agent agent 7588 Jul 17 14:47 TINGDISK_readme.txt -rw-rw-r-- 1 agent agent 2947 Jul 18 22:09 tone_autolock.py -rw-r--r-- 1 agent agent 384044 Jul 18 22:13 tone_capture_2930Hz.wav [2026-07-19 08:46:15] thinking: [not recorded in transcript] [2026-07-19 08:46:16] tool use: Bash command: ls -la /home/agent/TE_ting/scratchpad/; echo ---; sed -n 1,120p /home/agent/TE_ting/scratchpad/rp.py description: Inspect scratchpad helper [2026-07-19 08:46:16] tool result: Bash total 100 drwxrwxr-x 3 agent agent 4096 Jul 19 08:13 . drwxrwxr-x 7 agent agent 4096 Jul 19 08:31 .. -rw-rw-r-- 1 agent agent 1242 Jul 19 08:13 device_main.py -rw-rw-r-- 1 agent agent 4383 Jul 18 20:11 device_tone.py -rw-rw-r-- 1 agent agent 5978 Jul 18 22:07 device_tone_slave.py -rw-rw-r-- 1 agent agent 1418 Jul 18 22:04 dma_reset.py -rw-rw-r-- 1 agent agent 329 Jul 18 20:48 lock_test.py -rw-rw-r-- 1 agent agent 1185 Jul 18 11:23 measure_freq.py -rw-rw-r-- 1 agent agent 2828 Jul 18 11:40 play_loopback.py -rw-rw-r-- 1 agent agent 2143 Jul 18 20:46 probe_phase.py drwxrwxr-x 2 agent agent 4096 Jul 18 19:42 __pycache__ -rw-rw-r-- 1 agent agent 1809 Jul 18 11:23 repl.py -rw-rw-r-- 1 agent agent 2764 Jul 18 11:23 rp.py -rw-rw-r-- 1 agent agent 5328 Jul 18 21:55 rx_probe.py -rw-rw-r-- 1 agent agent 1014 Jul 18 11:23 sweep_mclk.py -rw-rw-r-- 1 agent agent 1406 Jul 18 11:23 t1_baseline.py -rw-rw-r-- 1 agent agent 1495 Jul 18 11:23 t2b_adcdat_pull.py -rw-rw-r-- 1 agent agent 1626 Jul 18 11:23 t2c_oe_tri.py -rw-rw-r-- 1 agent agent 1718 Jul 18 11:23 t2_din.py -rw-rw-r-- 1 agent agent 2386 Jul 18 11:23 t3_dout.py -rw-rw-r-- 1 agent agent 2636 Jul 18 20:29 test_d2a_loop.py -rw-rw-r-- 1 agent agent 2214 Jul 18 21:11 tone_autolock.py --- #!/usr/bin/env python3 """Robust raw-REPL exec helper for the EP-2350 over /dev/ttyACM0. Enters raw REPL, sends code + ctrl-D, and parses the framed reply: b"OK" b"\\x04" b"\\x04" b">" Reads by scanning for the two \\x04 terminators rather than relying on endswith(), which was racy when output arrived in multiple chunks. """ import sys, time, serial PORT = "/dev/ttyACM0" BAUD = 115200 def _drain_until(ser, marker, timeout): marker = marker if isinstance(marker, bytes) else marker.encode() buf = bytearray() deadline = time.time() + timeout while time.time() < deadline: n = ser.in_waiting if n: buf += ser.read(n) i = buf.find(marker) if i != -1: return bytes(buf[:i]), bytes(buf[i + len(marker):]) else: time.sleep(0.005) raise TimeoutError("marker %r not seen; got %r" % (marker, bytes(buf[-200:]))) def run(code, timeout=15.0): if isinstance(code, str): code = code.encode() with serial.Serial(PORT, BAUD, timeout=0.1) as ser: ser.write(b"\r\x03\x03") # interrupt any running program time.sleep(0.2) ser.reset_input_buffer() ser.write(b"\x01") # ctrl-A -> raw REPL _drain_until(ser, b"raw REPL; CTRL-B to exit\r\n>", timeout=3.0) ser.reset_input_buffer() ser.write(code) ser.write(b"\x04") # ctrl-D -> execute # device echoes "OK" once accepted _, rest = _drain_until(ser, b"OK", timeout=5.0) # stdout up to first \x04 stdout, rest = _drain_until_buffered(ser, rest, b"\x04", timeout) stderr, rest = _drain_until_buffered(ser, rest, b"\x04", timeout) ser.write(b"\x02") # ctrl-B -> friendly REPL return stdout.decode(errors="replace"), stderr.decode(errors="replace") def _drain_until_buffered(ser, pre, marker, timeout): """Like _drain_until but seeds with already-read bytes `pre`.""" buf = bytearray(pre) i = buf.find(marker) if i != -1: return bytes(buf[:i]), bytes(buf[i + len(marker):]) deadline = time.time() + timeout while time.time() < deadline: n = ser.in_waiting if n: buf += ser.read(n) i = buf.find(marker) if i != -1: return bytes(buf[:i]), bytes(buf[i + len(marker):]) else: time.sleep(0.005) raise TimeoutError("marker %r not seen; got %r" % (marker, bytes(buf[-200:]))) if __name__ == "__main__": src = sys.stdin.read() if len(sys.argv) < 2 else open(sys.argv[1]).read() o, e = run(src) sys.stdout.write(o) if e.strip(): sys.stderr.write("\n--- STDERR ---\n" + e) [2026-07-19 08:46:30] thinking: [not recorded in transcript] [2026-07-19 08:46:33] tool use: Bash command: ls /dev/ttyACM* 2>&1; python3 -c " import sys; sys.path.insert(0,'scratchpad') import rp o,e=rp.run(''' import sys, machine print(sys.implementation) from machine import mem32 SIO=0xd0000000 print(\"IN %08x\" % mem32[SIO+0x004]) print(\"OUT %08x\" % mem32[SIO+0x010]) print(\"OE %08x\" % mem32[SIO+0x030]) ''') print(o); print('ERR',e) " description: Check REPL and SIO state [2026-07-19 08:46:33] tool result: Bash /dev/ttyACM0 (name='micropython', version=(1, 25, 0, ''), _machine='Raspberry Pi Pico2 with RP2350', _mpy=7942, _build='RPI_PICO2') IN 00000000 OUT 00000000 OE 00000000 ERR [2026-07-19 08:46:40] thinking: [not recorded in transcript] [2026-07-19 08:46:43] tool use: Bash command: python3 -c " import sys; sys.path.insert(0,'scratchpad') import rp o,e=rp.run(''' from machine import Pin, mem32 SIO=0xd0000000 hold=Pin(2,Pin.OUT,value=1) pins={} for i in range(30): if i==2: continue pins[i]=Pin(i,Pin.IN,Pin.PULL_UP) import time time.sleep_ms(50) v=mem32[SIO+0x004] print(\"IN %08x\" % v) print(\"low:\", [i for i in range(30) if i!=2 and not (v>>i)&1]) ''') print(o); print('ERR',e) " description: Pull-up scan baseline [2026-07-19 08:46:43] tool result: Bash IN 3ff7ffff low: [19] ERR [2026-07-19 08:46:53] thinking: [not recorded in transcript] [2026-07-19 08:46:54] agent: Pull-up scan works — only GP19 low at rest. Now a live change monitor so we can catch presses. [2026-07-19 08:47:08] tool use: Write file_path: /home/agent/TE_ting/scratchpad/btn_monitor.py content: #!/usr/bin/env python3 """Live GPIO change monitor for EP-2350 button hunting. Configures every GPIO except GP2 (power hold) as input with an internal pull-up, then streams every debounced change of GPIO_IN to stdout as t= IN= low=[pins reading 0] changed=[pins that moved] Usage: python3 btn_monitor.py [seconds] Ctrl-C to stop early; the device is left with GP2 still held high. """ import sys, time, serial PORT = "/dev/ttyACM0" DUR = float(sys.argv[1]) if len(sys.argv) > 1 else 60.0 DEV = """ from machine import Pin, mem32 import time SIO = 0xd0000000 hold = Pin(2, Pin.OUT, value=1) pins = [Pin(i, Pin.IN, Pin.PULL_UP) for i in range(30) if i != 2] MASK = 0x3fffffff & ~(1 << 2) def rd(): return mem32[SIO + 0x004] & MASK prev = rd() t0 = time.ticks_ms() print("BASE %08x" % prev) end = t0 + int(%f * 1000) while time.ticks_diff(end, time.ticks_ms()) > 0: v = rd() if v != prev: time.sleep_ms(8) # debounce settle v = rd() if v != prev: print("%%6d %%08x %%08x" %% (time.ticks_diff(time.ticks_ms(), t0), v, v ^ prev)) prev = v time.sleep_ms(2) print("DONE") """ % DUR def fmt(line): parts = line.split() if len(parts) != 3: return line try: t, v, ch = int(parts[0]), int(parts[1], 16), int(parts[2], 16) except ValueError: return line low = [i for i in range(30) if i != 2 and not (v >> i) & 1] rel = [i for i in range(30) if (ch >> i) & 1 and (v >> i) & 1] prs = [i for i in range(30) if (ch >> i) & 1 and not (v >> i) & 1] bits = [] if prs: bits.append("PRESSED(->0) " + ",".join("GP%d" % i for i in prs)) if rel: bits.append("RELEASED(->1) " + ",".join("GP%d" % i for i in rel)) return "t=%7.2fs %-40s low=%s" % ( t / 1000.0, " ".join(bits), ",".join("GP%d" % i for i in low) or "-") def main(): with serial.Serial(PORT, 115200, timeout=0.1) as ser: ser.write(b"\r\x03\x03") time.sleep(0.2) ser.reset_input_buffer() ser.write(b"\x01") time.sleep(0.3) ser.reset_input_buffer() ser.write(DEV.encode()) ser.write(b"\x04") buf = b"" deadline = time.time() + DUR + 15 while time.time() < deadline: n = ser.in_waiting if n: buf += ser.read(n) while b"\n" in buf: line, buf = buf.split(b"\n", 1) s = line.decode(errors="replace").strip().lstrip("OK").strip() if not s or s == ">": continue if s.startswith("DONE"): print("--- done ---") ser.write(b"\x02") return print(fmt(s), flush=True) else: time.sleep(0.005) ser.write(b"\x03\x02") if __name__ == "__main__": try: main() except KeyboardInterrupt: pass [2026-07-19 08:47:14] tool result: Write File created successfully at: /home/agent/TE_ting/scratchpad/btn_monitor.py (file state is current in your context — no need to Read it back) [2026-07-19 08:47:23] thinking: [not recorded in transcript] [2026-07-19 08:47:24] agent: Tooling ready. Let me do a quick 20-second validation run first. **Please do this now:** when I say go, press and release **one** of the side buttons a couple of times (whichever is easiest to reach), then leave everything alone. Starting the monitor now — you have ~20 seconds. [2026-07-19 08:47:25] tool use: Bash command: python3 scratchpad/btn_monitor.py 20 description: 20s validation button monitor timeout: 60000 [2026-07-19 08:47:25] tool result (error): Bash Exit code 1 Traceback (most recent call last): File "/home/agent/TE_ting/scratchpad/btn_monitor.py", line 16, in DEV = """ ~~~ ...<21 lines>... print("DONE") ~~~~~~~~~~~~~ """ % DUR ~~~~^~~~~ TypeError: %x format: an integer is required, not float [2026-07-19 08:47:28] thinking: [not recorded in transcript] [2026-07-19 08:47:30] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/scratchpad/btn_monitor.py old_string: print("BASE %08x" % prev) t0 = time.ticks_ms() new_string: print("BASE %08x" % prev) t0 = time.ticks_ms() [2026-07-19 08:47:30] tool result (error): Edit String to replace not found in file. String: print("BASE %08x" % prev) t0 = time.ticks_ms() [2026-07-19 08:47:32] agent: Let me fix the string interpolation collision properly. [2026-07-19 08:47:33] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/scratchpad/btn_monitor.py old_string: end = t0 + int(%f * 1000) new_string: end = t0 + int(__DUR__ * 1000) [2026-07-19 08:47:38] tool result: Edit The file /home/agent/TE_ting/scratchpad/btn_monitor.py has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 08:47:42] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/scratchpad/btn_monitor.py old_string: print("%%6d %%08x %%08x" %% (time.ticks_diff(time.ticks_ms(), t0), v, v ^ prev)) prev = v time.sleep_ms(2) print("DONE") """ % DUR new_string: print("%6d %08x %08x" % (time.ticks_diff(time.ticks_ms(), t0), v, v ^ prev)) prev = v time.sleep_ms(2) print("DONE") """.replace("__DUR__", repr(DUR)) [2026-07-19 08:47:45] tool result: Edit The file /home/agent/TE_ting/scratchpad/btn_monitor.py has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 08:47:48] agent: **Go — press and release one side button a few times over the next 20 seconds.** [2026-07-19 08:47:48] tool use: Bash command: python3 scratchpad/btn_monitor.py 20 description: 20s validation button monitor timeout: 60000 [2026-07-19 08:48:09] tool result: Bash BASE 3ff7fffb t= 0.91s PRESSED(->0) GP21 low=GP19,GP21 t= 1.35s RELEASED(->1) GP21 low=GP19 t= 2.04s PRESSED(->0) GP21 low=GP19,GP21 t= 2.53s RELEASED(->1) GP21 low=GP19 t= 3.42s PRESSED(->0) GP21 low=GP19,GP21 t= 3.89s RELEASED(->1) GP21 low=GP19 --- done --- [2026-07-19 08:48:17] thinking: [not recorded in transcript] [2026-07-19 08:48:20] agent: GP21 confirmed as a side button. Now the full mapping run — **70 seconds**, and order matters more than exact timing. Do this sequence, pausing ~3s between steps: 1. **Wait ~5s** doing nothing. 2. **Top side button** (nearest the handle) — press & release **twice**. 3. **Middle side button** — press & release **twice**. 4. **Bottom side button** — press & release **twice**. 5. **Release the handle** (let it slide out) and leave it out ~5s. 6. **Press the handle back in** all the way and hold it. Tell me if your side buttons aren't in a top/middle/bottom arrangement — otherwise, **go**: [2026-07-19 08:48:21] tool use: Bash command: python3 scratchpad/btn_monitor.py 70 description: 70s full button mapping run timeout: 120000 [2026-07-19 08:49:32] tool result: Bash BASE 3ff7fffb t= 30.04s PRESSED(->0) GP21 low=GP19,GP21 t= 30.31s RELEASED(->1) GP21 low=GP19 t= 30.78s PRESSED(->0) GP21 low=GP19,GP21 t= 31.09s RELEASED(->1) GP21 low=GP19 t= 34.09s PRESSED(->0) GP3 low=GP3,GP19 t= 34.37s RELEASED(->1) GP3 low=GP19 t= 35.05s PRESSED(->0) GP3 low=GP3,GP19 t= 35.36s RELEASED(->1) GP3 low=GP19 t= 38.66s PRESSED(->0) GP1 low=GP1,GP19 t= 39.00s RELEASED(->1) GP1 low=GP19 t= 39.71s PRESSED(->0) GP1 low=GP1,GP19 t= 40.12s RELEASED(->1) GP1 low=GP19 t= 46.03s RELEASED(->1) GP19 low=- t= 46.20s PRESSED(->0) GP20 low=GP20 t= 52.62s RELEASED(->1) GP20 low=- t= 52.94s PRESSED(->0) GP19 low=GP19 t= 54.60s PRESSED(->0) GP21 low=GP19,GP21 t= 55.07s RELEASED(->1) GP21 low=GP19 --- done --- [2026-07-19 08:49:41] thinking: [not recorded in transcript] [2026-07-19 08:49:42] agent: All four pins found. One quick confirmation so I don't mislabel which side button is which — the run started ~25s late, so I want to verify the ordering directly. **Press ONLY the top side button (nearest the handle), twice** — 15 seconds: [2026-07-19 08:49:43] tool use: Bash command: python3 scratchpad/btn_monitor.py 15 description: Verify top side button timeout: 60000 [2026-07-19 08:49:58] tool result: Bash BASE 3ff7fffb t= 10.53s PRESSED(->0) GP21 low=GP19,GP21 t= 10.88s RELEASED(->1) GP21 low=GP19 t= 11.39s PRESSED(->0) GP21 low=GP19,GP21 t= 11.83s RELEASED(->1) GP21 low=GP19 --- done --- [2026-07-19 08:50:01] thinking: [not recorded in transcript] [2026-07-19 08:50:01] agent: Confirmed. Writing this up. [2026-07-19 08:50:22] tool use: Write file_path: /home/agent/TE_ting/button_findings.md content: # EP-2350 button pin map — SOLVED Session date: 2026-07-19. Method: stock MicroPython v1.25.0 (RPI_PICO2) over the raw REPL, all GPIOs configured as inputs with internal pull-ups, streaming a debounced `GPIO_IN` change log (`scratchpad/btn_monitor.py`) while the user pressed buttons in a known order. ## TL;DR | Button | GPIO | Sense | |--------|-----:|-------| | Side button — **top** (nearest handle) | **GP21** | 0 = pressed | | Side button — **middle** | **GP3** | 0 = pressed | | Side button — **bottom** | **GP1** | 0 = pressed | | Handle **fully in** (travel end-stop) | **GP19** | 0 = pressed | | Handle **at rest / not held** | **GP20** | **0 = handle released**, 1 = handle held | All five are simple switches to ground. None have external pull-ups — they read as floating unless the MCU's internal pull-up is enabled, so every button needs `Pin(n, Pin.IN, Pin.PULL_UP)`. ```python from machine import Pin hold = Pin(2, Pin.OUT, value=1) # power latch first, always btn_top = Pin(21, Pin.IN, Pin.PULL_UP) btn_mid = Pin(3, Pin.IN, Pin.PULL_UP) btn_bot = Pin(1, Pin.IN, Pin.PULL_UP) handle_in = Pin(19, Pin.IN, Pin.PULL_UP) # 0 = handle pushed all the way in handle_rest = Pin(20, Pin.IN, Pin.PULL_UP) # 0 = handle out, 1 = handle held ``` ## The handle is a two-stage switch GP19 and GP20 are two separate switches on the same mechanism, and the raw log shows them changing in sequence rather than together: ``` t=46.03s GP19 -> 1 handle starts moving out t=46.20s GP20 -> 0 (+170 ms) handle reaches rest t=52.62s GP20 -> 1 handle starts moving in t=52.94s GP19 -> 0 (+320 ms) handle reaches full travel ``` So there is a dead band in the middle of the travel where **both** read 1 (GP19 released, GP20 released). Useful consequences: - `GP20 == 1` is the earliest possible "user is touching the handle" signal — it fires ~300 ms before GP19 confirms full insertion. - `GP19 == 0` means fully seated, which is what gates the power-on path (see `power_hold_findings.md` — the handle switch supplies power directly until the GP2 latch is asserted). - Neither pin alone tells you the handle position; use the pair. ## Resolves an open question `power_hold_findings.md` listed GP20 as *"read externally-low on one run and floating on another. Possibly a second switch."* It is a second switch, and the inconsistency is explained: GP20's level depends on handle position, and the two earlier probe runs happened with the handle in different states. The same file's "external-drive map of every GPIO" should be read with the caveat that **GP1, GP3 and GP21 were listed as floating** — they are floating only because no button was being pressed during that survey. ## Method notes - A pull-up scan is the right probe for these pins and is **not** affected by the RP2350-E9 erratum, which only corrupts internal-*pull-down* readings. Driving nothing and pulling up is also safe on live hardware. - `GPIO_IN` reads all-zero on a fresh MicroPython boot because RP2350 pads default to input-disabled (`IE=0`). Pins must be instantiated as `Pin` objects before `mem32[SIO+0x004]` means anything. - GP2 must be driven high at the start of any button session, otherwise the unit powers off the moment the handle is released — which is exactly the event you want to observe. - Baseline `GPIO_IN` with the handle in and nothing pressed: `0x3ff7ffff` (only GP19 low). ## Remaining unidentified pins Unchanged by this session: GP16 (PIO clock output under TE firmware), GP25, and the `get_vbus` digital sense line. No button accounts for any of them. [2026-07-19 08:50:25] tool result: Write File created successfully at: /home/agent/TE_ting/button_findings.md (file state is current in your context — no need to Read it back) [2026-07-19 08:50:30] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/power_hold_findings.md old_string: - **GP20** — read externally-low on one run and floating on another. Possibly a second switch, or a line whose state depends on handle-power vs latch-power. new_string: - ~~**GP20**~~ — **RESOLVED 2026-07-19**: it is the second handle switch (0 = handle at rest / not held). The run-to-run inconsistency was simply the handle being in different positions. See `button_findings.md`, which also maps the three side buttons to GP21 / GP3 / GP1. [2026-07-19 08:50:36] tool result: Edit The file /home/agent/TE_ting/power_hold_findings.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 08:50:45] tool use: Write file_path: /home/agent/.claude/projects/-home-agent-TE-ting/memory/ep2350-button-map.md content: --- name: ep2350-button-map description: EP-2350 button GPIOs — side buttons GP21/GP3/GP1, two-stage handle GP19/GP20, all active-low needing internal pull-ups metadata: type: project --- EP-2350 buttons, all switches to ground with **no external pull-ups** (need `Pin(n, Pin.IN, Pin.PULL_UP)`), solved 2026-07-19: - Side buttons: **GP21** top (nearest handle), **GP3** middle, **GP1** bottom - Handle **fully in**: **GP19** (0 = pressed) — see [[ep2350-power-latch]] - Handle **at rest / not held**: **GP20** (0 = handle out, 1 = handle held) The handle is two-stage with a dead band where both read 1; GP20 fires ~300 ms before GP19 when inserting. GP20 was previously an open question in `power_hold_findings.md` (looked "sometimes floating") — it was just handle position varying between runs. **Why:** these were unknown, and a pull-up scan was the probe that worked. **How to apply:** for live button hunting use `scratchpad/btn_monitor.py` — pull-up every GPIO, stream debounced `GPIO_IN` changes, have the user press in a known order. Pull-ups are safe on live hardware and immune to the RP2350-E9 erratum (which only breaks internal-pull-*down* probing). Assert the GP2 latch first, and remember `GPIO_IN` reads 0 until pins are instantiated (pads boot with `IE=0`). Full writeup: `button_findings.md`. [2026-07-19 08:50:45] tool result: Write File created successfully at: /home/agent/.claude/projects/-home-agent-TE-ting/memory/ep2350-button-map.md [2026-07-19 08:50:48] tool use: Read file_path: /home/agent/.claude/projects/-home-agent-TE-ting/memory/MEMORY.md [2026-07-19 08:50:48] tool result: Read 1 - [EP-2350 REPL access](ep2350-repl-access.md) — use pyserial raw-REPL (not mpremote); no `machine` module; never actively drive pins on live firmware 2 - [EP-2350 pin map](ep2350-pin-map.md) — I²C=I2C1 GPIO14/15; I²S GPIO8-11 + MCLK GPIO12 (not 16) 3 - [EP-2350 power latch](ep2350-power-latch.md) — SOLVED: power hold = GPIO2 (high=on, low=off); handle sense = GPIO19; no PMIC on I²C 4 - [EP-2350 custom bootloader](ep2350-custom-bootloader.md) — TING BOOT is TE's flash bootloader (2367:0620), not RP2350 ROM; picotool unusable; drag-drop UF2 5 - [EP-2350 audio tone status](ep2350-audio-tone-status.md) — SOLVED: deterministic clean tone (codec-master + PIO slave-TX); fix was DMA CHAN_ABORT, not word-phase 6 [2026-07-19 08:50:52] tool use: Edit replace_all: false file_path: /home/agent/.claude/projects/-home-agent-TE-ting/memory/MEMORY.md old_string: - [EP-2350 audio tone status](ep2350-audio-tone-status.md) new_string: - [EP-2350 button map](ep2350-button-map.md) — SOLVED: side buttons GP21/GP3/GP1 (top/mid/bottom); handle is two-stage GP19 (in) + GP20 (at rest); all active-low, need internal pull-ups - [EP-2350 audio tone status](ep2350-audio-tone-status.md) [2026-07-19 08:50:52] tool result: Edit The file /home/agent/.claude/projects/-home-agent-TE-ting/memory/MEMORY.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 08:51:03] agent: All five buttons are mapped. | Button | GPIO | Sense | |--------|-----:|-------| | Side — top (nearest handle) | **GP21** | 0 = pressed | | Side — middle | **GP3** | 0 = pressed | | Side — bottom | **GP1** | 0 = pressed | | Handle fully in | **GP19** | 0 = pressed | | Handle at rest / not held | **GP20** | 0 = handle out, 1 = handle held | **How it was found:** every GPIO configured as input with an internal pull-up, then a debounced `GPIO_IN` change stream while you pressed things. Two details made it work — `GPIO_IN` reads all-zero until pins are instantiated (RP2350 pads boot with input disabled), and a pull-up probe sidesteps the RP2350-E9 erratum that had made earlier pull-down surveys unreliable. **The interesting result** is the handle: GP19 and GP20 are two switches on one mechanism, and the log caught them firing in sequence rather than together. ``` t=46.03s GP19 -> 1 handle starts moving out t=46.20s GP20 -> 0 (+170 ms) handle reaches rest t=52.62s GP20 -> 1 handle starts moving in t=52.94s GP19 -> 0 (+320 ms) fully seated ``` There's a dead band mid-travel where both read 1, so neither pin alone gives you handle position — use the pair. Practically, `GP20 == 1` is your earliest "user grabbed the handle" signal, ~300 ms ahead of GP19 confirming full insertion. This also resolves an open question in `power_hold_findings.md`, which had GP20 as "externally-low on one run, floating on another, possibly a second switch." It is a second switch — the runs just happened with the handle in different positions. I've marked that entry resolved. One caveat worth carrying forward: that same file's pin survey lists GP1, GP3 and GP21 as floating, which is only true because no button was held during it. Written up in `button_findings.md`; the reusable probe is `scratchpad/btn_monitor.py` (takes a duration in seconds). Remaining unidentified pins are unchanged: GP16, GP25, and the `get_vbus` sense line. [2026-07-19 08:55:38] user: Thank you. There is also a volume knob on the device. I'm not sure if it is hooked to the RP2350, or directly to the audio codec chip. Can you help figure that out, and if connected to RP2350 make a test to find the pin that its on. [2026-07-19 08:55:58] thinking: [not recorded in transcript] [2026-07-19 08:56:01] agent: Good question — and the existing data gives a useful prior. The earlier ADC survey found GP26 and GP27 genuinely floating and GP28 a fixed 1:2 divider, so a **potentiometer on an RP2350 ADC pin looks unlikely** — unless the survey happened to catch a rheostat-style pot at one extreme. A rotary **encoder** on two digital pins is the more likely wiring if it's on the MCU at all. Let me test both in one pass: digital change monitoring plus continuous ADC sampling while you turn the knob. [2026-07-19 08:56:17] tool use: Write file_path: /home/agent/TE_ting/scratchpad/knob_monitor.py content: #!/usr/bin/env python3 """Hunt for the EP-2350 volume knob: digital + analog at the same time. Digital: every GPIO except GP2 (power hold) and GP26-29 (claimed by the ADC) gets an internal pull-up; debounced GPIO_IN changes are streamed. Catches a rotary encoder (two pins chattering in quadrature) or a switch. Analog: ADC0-3 (GP26-29) sampled continuously; a reading is reported whenever it moves more than THRESH counts from the last reported value. Catches a potentiometer wiper. Usage: python3 knob_monitor.py [seconds] """ import sys, time, serial PORT = "/dev/ttyACM0" DUR = float(sys.argv[1]) if len(sys.argv) > 1 else 40.0 DEV = """ from machine import Pin, ADC, mem32 import time SIO = 0xd0000000 hold = Pin(2, Pin.OUT, value=1) DIG = [i for i in range(30) if i != 2 and not (26 <= i <= 29)] pins = [Pin(i, Pin.IN, Pin.PULL_UP) for i in DIG] MASK = 0 for i in DIG: MASK |= 1 << i adcs = [ADC(i) for i in range(4)] THRESH = 400 def rd(): return mem32[SIO + 0x004] & MASK prev = rd() last = [a.read_u16() for a in adcs] t0 = time.ticks_ms() print("BASE %08x A %d %d %d %d" % (prev, last[0], last[1], last[2], last[3])) end = t0 + int(__DUR__ * 1000) while time.ticks_diff(end, time.ticks_ms()) > 0: v = rd() if v != prev: time.sleep_ms(5) v = rd() if v != prev: print("D %6d %08x %08x" % (time.ticks_diff(time.ticks_ms(), t0), v, v ^ prev)) prev = v for j in range(4): c = adcs[j].read_u16() if abs(c - last[j]) > THRESH: print("A %6d %d %d" % (time.ticks_diff(time.ticks_ms(), t0), j, c)) last[j] = c time.sleep_ms(2) print("DONE") """.replace("__DUR__", repr(DUR)) DIG = [i for i in range(30) if i != 2 and not (26 <= i <= 29)] def fmt(s): p = s.split() try: if p[0] == "D": t, v, ch = int(p[1]), int(p[2], 16), int(p[3], 16) low = [i for i in DIG if not (v >> i) & 1] prs = [i for i in DIG if (ch >> i) & 1 and not (v >> i) & 1] rel = [i for i in DIG if (ch >> i) & 1 and (v >> i) & 1] bits = [] if prs: bits.append("->0 " + ",".join("GP%d" % i for i in prs)) if rel: bits.append("->1 " + ",".join("GP%d" % i for i in rel)) return "t=%7.2fs DIG %-28s low=%s" % ( t / 1000.0, " ".join(bits), ",".join("GP%d" % i for i in low) or "-") if p[0] == "A": t, ch, val = int(p[1]), int(p[2]), int(p[3]) return "t=%7.2fs ADC%d (GP%d) = %5d %.3f V" % ( t / 1000.0, ch, 26 + ch, val, val * 3.3 / 65535) except (ValueError, IndexError): pass return s def main(): with serial.Serial(PORT, 115200, timeout=0.1) as ser: ser.write(b"\r\x03\x03") time.sleep(0.2) ser.reset_input_buffer() ser.write(b"\x01") time.sleep(0.3) ser.reset_input_buffer() ser.write(DEV.encode()) ser.write(b"\x04") buf = b"" deadline = time.time() + DUR + 15 while time.time() < deadline: n = ser.in_waiting if n: buf += ser.read(n) while b"\n" in buf: line, buf = buf.split(b"\n", 1) s = line.decode(errors="replace").strip().lstrip("OK").strip() if not s or s == ">": continue if s.startswith("DONE"): print("--- done ---") ser.write(b"\x02") return print(fmt(s), flush=True) else: time.sleep(0.005) ser.write(b"\x03\x02") if __name__ == "__main__": try: main() except KeyboardInterrupt: pass [2026-07-19 08:56:21] tool result: Write File created successfully at: /home/agent/TE_ting/scratchpad/knob_monitor.py (file state is current in your context — no need to Read it back) [2026-07-19 08:56:24] agent: **40 seconds — turn the volume knob slowly through its full range, then back, then give it a few quick spins.** If it also clicks in as a button, press it a couple of times at the end. [2026-07-19 08:56:25] tool use: Bash command: python3 scratchpad/knob_monitor.py 40 description: 40s knob digital+analog monitor timeout: 90000 [2026-07-19 08:57:06] tool result: Bash BASE 03effffb A 54717 63135 38729 65327 t= 0.00s ADC0 (GP26) = 64175 3.232 V t= 5.25s ADC3 (GP29) = 64895 3.268 V t= 5.27s ADC3 (GP29) = 64447 3.245 V t= 5.28s ADC3 (GP29) = 63983 3.222 V t= 5.28s ADC3 (GP29) = 63455 3.195 V t= 5.29s ADC3 (GP29) = 63023 3.174 V t= 5.29s ADC3 (GP29) = 62447 3.145 V t= 5.30s ADC3 (GP29) = 61999 3.122 V t= 5.30s ADC3 (GP29) = 61438 3.094 V t= 5.31s ADC3 (GP29) = 60830 3.063 V t= 5.31s ADC3 (GP29) = 60334 3.038 V t= 5.32s ADC3 (GP29) = 59710 3.007 V t= 5.32s ADC3 (GP29) = 59022 2.972 V t= 5.32s ADC3 (GP29) = 58254 2.933 V t= 5.33s ADC3 (GP29) = 57774 2.909 V t= 5.33s ADC3 (GP29) = 57181 2.879 V t= 5.33s ADC3 (GP29) = 56541 2.847 V t= 5.34s ADC3 (GP29) = 55661 2.803 V t= 5.34s ADC3 (GP29) = 55197 2.779 V t= 5.34s ADC3 (GP29) = 54205 2.729 V t= 5.35s ADC3 (GP29) = 53389 2.688 V t= 5.35s ADC3 (GP29) = 52892 2.663 V t= 5.35s ADC3 (GP29) = 52140 2.625 V t= 5.36s ADC3 (GP29) = 51628 2.600 V t= 5.36s ADC3 (GP29) = 50956 2.566 V t= 5.36s ADC3 (GP29) = 50236 2.530 V t= 5.37s ADC3 (GP29) = 49660 2.501 V t= 5.37s ADC3 (GP29) = 49035 2.469 V t= 5.37s ADC3 (GP29) = 48427 2.439 V t= 5.38s ADC3 (GP29) = 47915 2.413 V t= 5.38s ADC3 (GP29) = 47451 2.389 V t= 5.39s ADC3 (GP29) = 47035 2.368 V t= 5.40s ADC3 (GP29) = 46603 2.347 V t= 5.53s ADC3 (GP29) = 46187 2.326 V t= 5.59s ADC3 (GP29) = 45755 2.304 V t= 5.62s ADC3 (GP29) = 45339 2.283 V t= 5.66s ADC3 (GP29) = 44938 2.263 V t= 5.68s ADC3 (GP29) = 44506 2.241 V t= 5.70s ADC3 (GP29) = 44058 2.219 V t= 5.71s ADC3 (GP29) = 43626 2.197 V t= 5.72s ADC3 (GP29) = 43194 2.175 V t= 5.75s ADC3 (GP29) = 42778 2.154 V t= 5.78s ADC3 (GP29) = 42330 2.132 V t= 5.80s ADC3 (GP29) = 41882 2.109 V t= 5.81s ADC3 (GP29) = 41466 2.088 V t= 5.82s ADC3 (GP29) = 41018 2.065 V t= 5.83s ADC3 (GP29) = 40553 2.042 V t= 5.84s ADC3 (GP29) = 40105 2.019 V t= 5.86s ADC3 (GP29) = 39609 1.995 V t= 5.86s ADC3 (GP29) = 39161 1.972 V t= 5.87s ADC3 (GP29) = 38617 1.945 V t= 5.87s ADC3 (GP29) = 38089 1.918 V t= 5.88s ADC3 (GP29) = 37433 1.885 V t= 5.88s ADC3 (GP29) = 36744 1.850 V t= 5.88s ADC3 (GP29) = 35880 1.807 V t= 5.89s ADC3 (GP29) = 34760 1.750 V t= 5.89s ADC3 (GP29) = 34280 1.726 V t= 5.89s ADC3 (GP29) = 33752 1.700 V t= 5.90s ADC3 (GP29) = 33064 1.665 V t= 5.90s ADC3 (GP29) = 32087 1.616 V t= 5.91s ADC3 (GP29) = 31287 1.575 V t= 5.91s ADC3 (GP29) = 30855 1.554 V t= 5.91s ADC3 (GP29) = 30119 1.517 V t= 5.92s ADC3 (GP29) = 29559 1.488 V t= 5.92s ADC3 (GP29) = 29063 1.463 V t= 5.92s ADC3 (GP29) = 28598 1.440 V t= 5.93s ADC3 (GP29) = 28038 1.412 V t= 5.94s ADC3 (GP29) = 27526 1.386 V t= 5.96s ADC3 (GP29) = 27078 1.364 V t= 5.99s ADC3 (GP29) = 26630 1.341 V t= 6.02s ADC3 (GP29) = 26150 1.317 V t= 6.04s ADC3 (GP29) = 25702 1.294 V t= 6.06s ADC3 (GP29) = 25254 1.272 V t= 6.08s ADC3 (GP29) = 24710 1.244 V t= 6.09s ADC3 (GP29) = 24277 1.222 V t= 6.10s ADC3 (GP29) = 23765 1.197 V t= 6.10s ADC3 (GP29) = 23301 1.173 V t= 6.12s ADC3 (GP29) = 22789 1.148 V t= 6.14s ADC3 (GP29) = 22373 1.127 V t= 6.15s ADC3 (GP29) = 21925 1.104 V t= 6.16s ADC3 (GP29) = 21445 1.080 V t= 6.17s ADC3 (GP29) = 17172 0.865 V t= 6.24s ADC3 (GP29) = 16740 0.843 V t= 6.25s ADC3 (GP29) = 16291 0.820 V t= 6.26s ADC3 (GP29) = 15827 0.797 V t= 6.27s ADC3 (GP29) = 15411 0.776 V t= 6.29s ADC3 (GP29) = 14915 0.751 V t= 6.30s ADC3 (GP29) = 14499 0.730 V t= 6.31s ADC3 (GP29) = 14019 0.706 V t= 6.32s ADC3 (GP29) = 13587 0.684 V t= 6.33s ADC3 (GP29) = 13171 0.663 V t= 6.35s ADC3 (GP29) = 12723 0.641 V t= 6.35s ADC3 (GP29) = 12258 0.617 V t= 6.36s ADC3 (GP29) = 11762 0.592 V t= 6.37s ADC3 (GP29) = 11314 0.570 V t= 6.38s ADC3 (GP29) = 10898 0.549 V t= 6.38s ADC3 (GP29) = 10386 0.523 V t= 6.39s ADC3 (GP29) = 9922 0.500 V t= 6.40s ADC3 (GP29) = 9442 0.475 V t= 6.42s ADC3 (GP29) = 8994 0.453 V t= 6.44s ADC3 (GP29) = 8578 0.432 V t= 6.45s ADC3 (GP29) = 8113 0.409 V t= 6.46s ADC3 (GP29) = 7697 0.388 V t= 6.47s ADC3 (GP29) = 7169 0.361 V t= 6.48s ADC3 (GP29) = 6721 0.338 V t= 6.49s ADC3 (GP29) = 6257 0.315 V t= 6.50s ADC3 (GP29) = 5761 0.290 V t= 6.51s ADC3 (GP29) = 5345 0.269 V t= 6.52s ADC3 (GP29) = 4897 0.247 V t= 6.54s ADC3 (GP29) = 4481 0.226 V t= 6.57s ADC3 (GP29) = 4048 0.204 V t= 6.58s ADC3 (GP29) = 3552 0.179 V t= 6.59s ADC3 (GP29) = 2944 0.148 V t= 6.60s ADC3 (GP29) = 2432 0.122 V t= 6.62s ADC3 (GP29) = 2000 0.101 V t= 6.62s ADC3 (GP29) = 1520 0.077 V t= 6.64s ADC3 (GP29) = 800 0.040 V t= 6.64s ADC3 (GP29) = 336 0.017 V t= 9.43s ADC3 (GP29) = 896 0.045 V t= 9.43s ADC3 (GP29) = 1344 0.068 V t= 9.44s ADC3 (GP29) = 1888 0.095 V t= 9.44s ADC3 (GP29) = 2480 0.125 V t= 9.45s ADC3 (GP29) = 2992 0.151 V t= 9.45s ADC3 (GP29) = 3456 0.174 V t= 9.45s ADC3 (GP29) = 3920 0.197 V t= 9.46s ADC3 (GP29) = 4369 0.220 V t= 9.46s ADC3 (GP29) = 4913 0.247 V t= 9.46s ADC3 (GP29) = 5489 0.276 V t= 9.46s ADC3 (GP29) = 5921 0.298 V t= 9.47s ADC3 (GP29) = 6673 0.336 V t= 9.47s ADC3 (GP29) = 7521 0.379 V t= 9.48s ADC3 (GP29) = 8145 0.410 V t= 9.48s ADC3 (GP29) = 8578 0.432 V t= 9.48s ADC3 (GP29) = 9218 0.464 V t= 9.49s ADC3 (GP29) = 9874 0.497 V t= 9.49s ADC3 (GP29) = 10498 0.529 V t= 9.49s ADC3 (GP29) = 11058 0.557 V t= 9.50s ADC3 (GP29) = 11586 0.583 V t= 9.51s ADC3 (GP29) = 12082 0.608 V t= 9.51s ADC3 (GP29) = 12547 0.632 V t= 9.52s ADC3 (GP29) = 12979 0.654 V t= 9.54s ADC3 (GP29) = 13395 0.675 V t= 9.60s ADC3 (GP29) = 13811 0.695 V t= 9.62s ADC3 (GP29) = 14227 0.716 V t= 9.65s ADC3 (GP29) = 14739 0.742 V t= 9.66s ADC3 (GP29) = 15235 0.767 V t= 9.67s ADC3 (GP29) = 15683 0.790 V t= 9.69s ADC3 (GP29) = 16131 0.812 V t= 9.69s ADC3 (GP29) = 16532 0.832 V t= 9.70s ADC3 (GP29) = 16948 0.853 V t= 9.71s ADC3 (GP29) = 17508 0.882 V t= 9.72s ADC3 (GP29) = 17924 0.903 V t= 9.73s ADC3 (GP29) = 18404 0.927 V t= 9.73s ADC3 (GP29) = 18868 0.950 V t= 9.74s ADC3 (GP29) = 19412 0.977 V t= 9.74s ADC3 (GP29) = 19828 0.998 V t= 9.75s ADC3 (GP29) = 20372 1.026 V t= 9.76s ADC3 (GP29) = 20773 1.046 V t= 9.76s ADC3 (GP29) = 21381 1.077 V t= 9.77s ADC3 (GP29) = 21909 1.103 V t= 9.77s ADC3 (GP29) = 22581 1.137 V t= 9.78s ADC3 (GP29) = 23237 1.170 V t= 9.78s ADC3 (GP29) = 23797 1.198 V t= 9.78s ADC3 (GP29) = 24213 1.219 V t= 9.79s ADC3 (GP29) = 24710 1.244 V t= 9.79s ADC3 (GP29) = 25222 1.270 V t= 9.79s ADC3 (GP29) = 25766 1.297 V t= 9.80s ADC3 (GP29) = 26454 1.332 V t= 9.80s ADC3 (GP29) = 26886 1.354 V t= 9.80s ADC3 (GP29) = 27318 1.376 V t= 9.81s ADC3 (GP29) = 28038 1.412 V t= 9.81s ADC3 (GP29) = 33592 1.692 V t= 9.81s ADC3 (GP29) = 34200 1.722 V t= 9.82s ADC3 (GP29) = 34760 1.750 V t= 9.82s ADC3 (GP29) = 35272 1.776 V t= 9.82s ADC3 (GP29) = 35720 1.799 V t= 9.83s ADC3 (GP29) = 36344 1.830 V t= 9.83s ADC3 (GP29) = 36969 1.862 V t= 9.84s ADC3 (GP29) = 37417 1.884 V t= 9.84s ADC3 (GP29) = 37945 1.911 V t= 9.85s ADC3 (GP29) = 38489 1.938 V t= 9.85s ADC3 (GP29) = 39017 1.965 V t= 9.86s ADC3 (GP29) = 39513 1.990 V t= 9.88s ADC3 (GP29) = 39929 2.011 V t= 9.89s ADC3 (GP29) = 40393 2.034 V t= 9.96s ADC3 (GP29) = 40809 2.055 V t= 10.00s ADC3 (GP29) = 41210 2.075 V t= 10.02s ADC3 (GP29) = 41674 2.098 V t= 10.03s ADC3 (GP29) = 42090 2.119 V t= 10.06s ADC3 (GP29) = 42522 2.141 V t= 10.08s ADC3 (GP29) = 42938 2.162 V t= 10.09s ADC3 (GP29) = 43354 2.183 V t= 10.11s ADC3 (GP29) = 43802 2.206 V t= 10.12s ADC3 (GP29) = 44234 2.227 V t= 10.13s ADC3 (GP29) = 44666 2.249 V t= 10.15s ADC3 (GP29) = 45115 2.272 V t= 10.17s ADC3 (GP29) = 45563 2.294 V t= 10.21s ADC3 (GP29) = 45979 2.315 V t= 10.23s ADC3 (GP29) = 46443 2.339 V t= 10.24s ADC3 (GP29) = 46891 2.361 V t= 10.25s ADC3 (GP29) = 47323 2.383 V t= 10.26s ADC3 (GP29) = 47803 2.407 V t= 10.28s ADC3 (GP29) = 48219 2.428 V t= 10.29s ADC3 (GP29) = 48635 2.449 V t= 10.31s ADC3 (GP29) = 49115 2.473 V t= 10.32s ADC3 (GP29) = 49564 2.496 V t= 10.34s ADC3 (GP29) = 50012 2.518 V t= 10.36s ADC3 (GP29) = 50428 2.539 V t= 10.37s ADC3 (GP29) = 50844 2.560 V t= 10.38s ADC3 (GP29) = 51324 2.584 V t= 10.39s ADC3 (GP29) = 51884 2.613 V t= 10.40s ADC3 (GP29) = 52316 2.634 V t= 10.41s ADC3 (GP29) = 52748 2.656 V t= 10.43s ADC3 (GP29) = 53164 2.677 V t= 10.46s ADC3 (GP29) = 53597 2.699 V t= 10.49s ADC3 (GP29) = 54061 2.722 V t= 10.51s ADC3 (GP29) = 54509 2.745 V t= 10.52s ADC3 (GP29) = 54957 2.767 V t= 10.54s ADC3 (GP29) = 55373 2.788 V t= 10.56s ADC3 (GP29) = 55805 2.810 V t= 10.59s ADC3 (GP29) = 56237 2.832 V t= 10.61s ADC3 (GP29) = 56669 2.854 V t= 10.62s ADC3 (GP29) = 57085 2.875 V t= 10.63s ADC3 (GP29) = 57518 2.896 V t= 10.65s ADC3 (GP29) = 57934 2.917 V t= 10.68s ADC3 (GP29) = 58350 2.938 V t= 10.70s ADC3 (GP29) = 58766 2.959 V t= 10.72s ADC3 (GP29) = 59182 2.980 V t= 10.75s ADC3 (GP29) = 59614 3.002 V t= 10.76s ADC3 (GP29) = 60062 3.024 V t= 10.80s ADC3 (GP29) = 60494 3.046 V t= 10.84s ADC3 (GP29) = 60974 3.070 V t= 10.87s ADC3 (GP29) = 61390 3.091 V t= 10.88s ADC3 (GP29) = 61839 3.114 V t= 10.90s ADC3 (GP29) = 62255 3.135 V t= 10.93s ADC3 (GP29) = 62671 3.156 V t= 10.94s ADC3 (GP29) = 63119 3.178 V t= 10.96s ADC3 (GP29) = 63583 3.202 V t= 10.98s ADC3 (GP29) = 64031 3.224 V t= 10.99s ADC3 (GP29) = 64479 3.247 V t= 11.02s ADC3 (GP29) = 64895 3.268 V t= 11.05s ADC3 (GP29) = 65311 3.289 V t= 14.38s ADC3 (GP29) = 64831 3.265 V t= 14.40s ADC3 (GP29) = 64415 3.244 V t= 14.41s ADC3 (GP29) = 63983 3.222 V t= 14.42s ADC3 (GP29) = 63503 3.198 V t= 14.43s ADC3 (GP29) = 62991 3.172 V t= 14.43s ADC3 (GP29) = 62431 3.144 V t= 14.44s ADC3 (GP29) = 61999 3.122 V t= 14.44s ADC3 (GP29) = 61487 3.096 V t= 14.45s ADC3 (GP29) = 60926 3.068 V t= 14.45s ADC3 (GP29) = 60334 3.038 V t= 14.46s ADC3 (GP29) = 59534 2.998 V t= 14.46s ADC3 (GP29) = 58814 2.962 V t= 14.46s ADC3 (GP29) = 58254 2.933 V t= 14.46s ADC3 (GP29) = 57742 2.908 V t= 14.46s ADC3 (GP29) = 57197 2.880 V t= 14.47s ADC3 (GP29) = 56781 2.859 V t= 14.47s ADC3 (GP29) = 56205 2.830 V t= 14.47s ADC3 (GP29) = 55581 2.799 V t= 14.47s ADC3 (GP29) = 55085 2.774 V t= 14.47s ADC3 (GP29) = 54445 2.742 V t= 14.48s ADC3 (GP29) = 53901 2.714 V t= 14.48s ADC3 (GP29) = 53373 2.688 V t= 14.48s ADC3 (GP29) = 52812 2.659 V t= 14.48s ADC3 (GP29) = 52060 2.621 V t= 14.49s ADC3 (GP29) = 51372 2.587 V t= 14.49s ADC3 (GP29) = 50764 2.556 V t= 14.50s ADC3 (GP29) = 50124 2.524 V t= 14.50s ADC3 (GP29) = 49580 2.497 V t= 14.51s ADC3 (GP29) = 48875 2.461 V t= 14.52s ADC3 (GP29) = 48459 2.440 V t= 14.53s ADC3 (GP29) = 47979 2.416 V t= 14.54s ADC3 (GP29) = 47563 2.395 V t= 14.61s ADC3 (GP29) = 47147 2.374 V t= 14.65s ADC3 (GP29) = 46731 2.353 V t= 14.76s ADC3 (GP29) = 46315 2.332 V t= 15.08s ADC3 (GP29) = 45867 2.310 V t= 15.11s ADC3 (GP29) = 45435 2.288 V t= 15.12s ADC3 (GP29) = 44890 2.260 V t= 15.13s ADC3 (GP29) = 44442 2.238 V t= 15.15s ADC3 (GP29) = 43978 2.215 V t= 15.15s ADC3 (GP29) = 43546 2.193 V t= 15.16s ADC3 (GP29) = 43050 2.168 V t= 15.17s ADC3 (GP29) = 42602 2.145 V t= 15.18s ADC3 (GP29) = 42170 2.123 V t= 15.19s ADC3 (GP29) = 41738 2.102 V t= 15.19s ADC3 (GP29) = 41290 2.079 V t= 15.20s ADC3 (GP29) = 40889 2.059 V t= 15.21s ADC3 (GP29) = 40425 2.036 V t= 15.21s ADC3 (GP29) = 39977 2.013 V t= 15.22s ADC3 (GP29) = 39497 1.989 V t= 15.23s ADC3 (GP29) = 39081 1.968 V t= 15.24s ADC3 (GP29) = 38489 1.938 V t= 15.25s ADC3 (GP29) = 37993 1.913 V t= 15.26s ADC3 (GP29) = 37449 1.886 V t= 15.27s ADC3 (GP29) = 36937 1.860 V t= 15.27s ADC3 (GP29) = 36536 1.840 V t= 15.28s ADC3 (GP29) = 36088 1.817 V t= 15.29s ADC3 (GP29) = 35640 1.795 V t= 15.29s ADC3 (GP29) = 35208 1.773 V t= 15.30s ADC3 (GP29) = 34728 1.749 V t= 15.31s ADC3 (GP29) = 34312 1.728 V t= 15.33s ADC3 (GP29) = 33864 1.705 V t= 15.35s ADC3 (GP29) = 33448 1.684 V t= 15.36s ADC3 (GP29) = 33032 1.663 V t= 15.37s ADC3 (GP29) = 32583 1.641 V t= 15.38s ADC3 (GP29) = 32039 1.613 V t= 15.38s ADC3 (GP29) = 31623 1.592 V t= 15.39s ADC3 (GP29) = 31095 1.566 V t= 15.40s ADC3 (GP29) = 30679 1.545 V t= 15.41s ADC3 (GP29) = 30263 1.524 V t= 15.42s ADC3 (GP29) = 29831 1.502 V t= 15.44s ADC3 (GP29) = 29399 1.480 V t= 15.49s ADC3 (GP29) = 28983 1.459 V t= 15.61s ADC3 (GP29) = 28582 1.439 V t= 15.93s ADC3 (GP29) = 29047 1.463 V t= 15.94s ADC3 (GP29) = 29623 1.492 V t= 15.95s ADC3 (GP29) = 30167 1.519 V t= 15.95s ADC3 (GP29) = 30855 1.554 V t= 15.95s ADC3 (GP29) = 31591 1.591 V t= 15.96s ADC3 (GP29) = 32151 1.619 V t= 15.96s ADC3 (GP29) = 32792 1.651 V t= 15.96s ADC3 (GP29) = 33640 1.694 V t= 15.97s ADC3 (GP29) = 34424 1.733 V t= 15.97s ADC3 (GP29) = 35080 1.766 V t= 15.97s ADC3 (GP29) = 35848 1.805 V t= 15.97s ADC3 (GP29) = 36536 1.840 V t= 15.98s ADC3 (GP29) = 39129 1.970 V t= 15.98s ADC3 (GP29) = 39641 1.996 V t= 15.99s ADC3 (GP29) = 40425 2.036 V t= 15.99s ADC3 (GP29) = 41114 2.070 V t= 15.99s ADC3 (GP29) = 41546 2.092 V t= 15.99s ADC3 (GP29) = 42074 2.119 V t= 16.00s ADC3 (GP29) = 42826 2.156 V t= 16.00s ADC3 (GP29) = 43658 2.198 V t= 16.00s ADC3 (GP29) = 44186 2.225 V t= 16.01s ADC3 (GP29) = 44666 2.249 V t= 16.01s ADC3 (GP29) = 45275 2.280 V t= 16.01s ADC3 (GP29) = 46011 2.317 V t= 16.01s ADC3 (GP29) = 46699 2.352 V t= 16.02s ADC3 (GP29) = 47675 2.401 V t= 16.02s ADC3 (GP29) = 48427 2.439 V t= 16.02s ADC3 (GP29) = 49035 2.469 V t= 16.02s ADC3 (GP29) = 49900 2.513 V t= 16.02s ADC3 (GP29) = 50444 2.540 V t= 16.02s ADC3 (GP29) = 51004 2.568 V t= 16.03s ADC3 (GP29) = 51692 2.603 V t= 16.03s ADC3 (GP29) = 52444 2.641 V t= 16.03s ADC3 (GP29) = 53212 2.679 V t= 16.04s ADC3 (GP29) = 53869 2.713 V t= 16.04s ADC3 (GP29) = 54397 2.739 V t= 16.05s ADC3 (GP29) = 55069 2.773 V t= 16.05s ADC3 (GP29) = 55693 2.804 V t= 16.05s ADC3 (GP29) = 56221 2.831 V t= 16.06s ADC3 (GP29) = 56797 2.860 V t= 16.07s ADC3 (GP29) = 57245 2.883 V t= 16.07s ADC3 (GP29) = 57758 2.908 V t= 16.08s ADC3 (GP29) = 58318 2.937 V t= 16.08s ADC3 (GP29) = 58766 2.959 V t= 16.09s ADC3 (GP29) = 59182 2.980 V t= 16.09s ADC3 (GP29) = 59614 3.002 V t= 16.10s ADC3 (GP29) = 60190 3.031 V t= 16.11s ADC3 (GP29) = 60670 3.055 V t= 16.11s ADC3 (GP29) = 61182 3.081 V t= 16.11s ADC3 (GP29) = 61663 3.105 V t= 16.12s ADC3 (GP29) = 62255 3.135 V t= 16.12s ADC3 (GP29) = 62927 3.169 V t= 16.13s ADC3 (GP29) = 63471 3.196 V t= 16.13s ADC3 (GP29) = 63967 3.221 V t= 16.14s ADC3 (GP29) = 64463 3.246 V t= 16.14s ADC3 (GP29) = 65007 3.273 V --- done --- [2026-07-19 08:57:26] thinking: [not recorded in transcript] [2026-07-19 08:57:29] agent: **Found it — and it's on the RP2350.** GP29 swept the full rail (0.017 V → 3.289 V) while you turned the knob, with zero digital activity anywhere. That's an analog potentiometer on **ADC3 / GP29**, not a rotary encoder, and not on the codec. This also explains a stale conclusion in the existing notes — more on that in a moment. First, one stepped measurement to characterize the taper. **25 seconds — set the knob to minimum, then step it to ~25%, ~50%, ~75%, and maximum, holding each for ~4 seconds.** Start at minimum now: [2026-07-19 08:57:32] tool use: Bash command: timeout 60 python3 -c " import sys; sys.path.insert(0,'scratchpad') import rp o,e=rp.run(''' from machine import Pin, ADC import time hold=Pin(2,Pin.OUT,value=1) a=ADC(3) t0=time.ticks_ms() out=[] while time.ticks_diff(time.ticks_ms(),t0) < 25000: s=0 for _ in range(16): s+=a.read_u16() out.append((time.ticks_diff(time.ticks_ms(),t0), s>>4)) time.sleep_ms(200) for t,v in out: print(\"%6d %5d %.3f\" % (t,v,v*3.3/65535)) ''', timeout=45) print(o); print('ERR',e) " description: Stepped GP29 pot characterization timeout: 90000 [2026-07-19 08:57:58] tool result: Bash 0 65343 3.290 200 65343 3.290 400 65342 3.290 600 65339 3.290 800 65340 3.290 1000 65339 3.290 1200 65341 3.290 1400 65343 3.290 1600 65341 3.290 1800 65341 3.290 2000 65338 3.290 2200 65339 3.290 2400 65341 3.290 2600 65339 3.290 2800 65345 3.290 3000 65339 3.290 3200 65340 3.290 3400 65341 3.290 3600 65339 3.290 3800 65341 3.290 4000 65342 3.290 4200 65337 3.290 4400 65342 3.290 4600 65336 3.290 4800 65342 3.290 5000 65338 3.290 5200 65340 3.290 5400 65337 3.290 5600 65340 3.290 5800 65341 3.290 6000 65341 3.290 6200 65342 3.290 6400 65338 3.290 6600 65341 3.290 6800 65336 3.290 7000 65338 3.290 7200 65342 3.290 7400 65336 3.290 7600 65339 3.290 7800 65341 3.290 8000 65340 3.290 8200 65344 3.290 8400 65338 3.290 8600 65336 3.290 8800 65340 3.290 9000 65343 3.290 9200 65344 3.290 9400 65339 3.290 9600 65342 3.290 9800 65340 3.290 10000 65339 3.290 10200 65341 3.290 10400 65336 3.290 10600 65341 3.290 10800 65340 3.290 11000 65341 3.290 11200 65341 3.290 11400 65342 3.290 11600 65344 3.290 11800 65341 3.290 12000 65339 3.290 12200 65341 3.290 12400 65340 3.290 12600 65340 3.290 12800 65340 3.290 13000 65332 3.290 13200 65341 3.290 13400 65339 3.290 13600 65341 3.290 13800 65340 3.290 14000 65336 3.290 14200 65340 3.290 14400 65338 3.290 14600 65336 3.290 14800 65335 3.290 15000 65342 3.290 15200 65340 3.290 15400 65341 3.290 15600 65340 3.290 15800 65340 3.290 16000 65339 3.290 16200 65340 3.290 16400 65338 3.290 16600 65340 3.290 16800 65334 3.290 17000 65342 3.290 17200 65342 3.290 17400 65337 3.290 17600 65338 3.290 17800 65338 3.290 18000 65340 3.290 18200 65341 3.290 18400 65335 3.290 18600 65341 3.290 18800 65340 3.290 19000 65342 3.290 19200 65342 3.290 19400 65336 3.290 19600 65337 3.290 19800 65338 3.290 20000 65340 3.290 20200 65340 3.290 20400 65345 3.290 20600 65342 3.290 20800 65341 3.290 21000 65341 3.290 21200 65340 3.290 21400 65338 3.290 21600 65340 3.290 21800 65339 3.290 22000 65342 3.290 22200 65339 3.290 22400 65336 3.290 22600 65339 3.290 22800 65342 3.290 23000 65338 3.290 23200 65345 3.290 23400 65340 3.290 23600 65340 3.290 23800 65342 3.290 24000 65338 3.290 24200 65338 3.290 24400 65340 3.290 24600 65341 3.290 24800 65339 3.290 ERR [2026-07-19 08:58:01] thinking: [not recorded in transcript] [2026-07-19 08:58:04] agent: The knob didn't move during that run — GP29 sat pinned at 65340 (3.290 V) the whole 25 s, which is the max-position reading. Let's retry the stepped test. **Turn the knob to minimum first, then start.** When you're ready, run the sweep: min → ~25% → ~50% → ~75% → max, about 4 seconds at each stop. [2026-07-19 08:58:12] tool use: Bash command: timeout 60 python3 -c " import sys; sys.path.insert(0,'scratchpad') import rp o,e=rp.run(''' from machine import Pin, ADC import time hold=Pin(2,Pin.OUT,value=1) a=ADC(3) t0=time.ticks_ms() out=[] while time.ticks_diff(time.ticks_ms(),t0) < 25000: s=0 for _ in range(16): s+=a.read_u16() out.append((time.ticks_diff(time.ticks_ms(),t0), s>>4)) time.sleep_ms(250) for t,v in out: print(\"%6d %5d %.3f\" % (t,v,v*3.3/65535)) ''', timeout=45) print(o); print('ERR',e) " | awk '{printf \"%s\n\", $0}' | python3 -c " import sys rows=[] for l in sys.stdin: p=l.split() if len(p)==3 and p[0].isdigit(): rows.append((int(p[0]),int(p[1]),float(p[2]))) else: print(l.rstrip()) # collapse runs of similar values into plateaus plat=[] for t,v,volt in rows: if plat and abs(v-plat[-1][-1][1])<800: plat[-1].append((t,v,volt)) else: plat.append([(t,v,volt)]) print('%-14s %-8s %-8s %s'%('window(s)','counts','volts','n')) for g in plat: if len(g)<2: continue vs=[x[1] for x in g] print('%5.1f-%5.1f %6d %6.3f %d'%(g[0][0]/1000,g[-1][0]/1000,sum(vs)//len(vs),sum(x[2] for x in g)/len(g),len(g))) " description: Stepped GP29 pot characterization, retry timeout: 90000 [2026-07-19 09:00:16] tool result (error): Bash The user doesn't want to proceed with this tool use. The tool use was rejected (eg. if it was a file edit, the new_string was NOT written to the file). STOP what you are doing and wait for the user to tell you how to proceed. Note: The user's next message may contain a correction or preference. Pay close attention — if they explain what went wrong or how they'd prefer you to work, consider saving that to memory for future sessions. [2026-07-19 09:00:16] user: [Request interrupted by user for tool use] [2026-07-19 09:00:30] user: Sorry, I had stepped away. We can do the 25, 50, 75, max test now if you want? [2026-07-19 09:00:33] thinking: [not recorded in transcript] [2026-07-19 09:00:34] agent: No problem. Let's do it — simple version, 25 seconds. **Start at minimum, then step: min → ~25% → ~50% → ~75% → max, ~5 s at each stop.** Go: [2026-07-19 09:00:36] tool use: Bash command: timeout 60 python3 -c " import sys; sys.path.insert(0,'scratchpad') import rp o,e=rp.run(''' from machine import Pin, ADC import time hold=Pin(2,Pin.OUT,value=1) a=ADC(3) t0=time.ticks_ms() out=[] while time.ticks_diff(time.ticks_ms(),t0) < 25000: s=0 for _ in range(16): s+=a.read_u16() out.append((time.ticks_diff(time.ticks_ms(),t0), s>>4)) time.sleep_ms(500) for t,v in out: print(\"%6d %5d %.3f\" % (t,v,v*3.3/65535)) ''', timeout=45) print(o); print('ERR',e) " description: Stepped GP29 pot characterization timeout: 90000 [2026-07-19 09:01:02] tool result: Bash 1 68 0.003 501 69 0.003 1001 69 0.003 1501 68 0.003 2001 67 0.003 2501 67 0.003 3001 67 0.003 3501 5331 0.268 4001 11600 0.584 4501 12986 0.654 5001 14544 0.732 5501 14772 0.744 6001 14773 0.744 6501 14768 0.744 7001 14771 0.744 7501 14769 0.744 8001 14767 0.744 8501 14766 0.744 9001 14763 0.743 9501 14769 0.744 10001 14767 0.744 10501 14766 0.744 11001 14766 0.744 11501 16869 0.849 12001 26966 1.358 12501 40262 2.027 13001 42736 2.152 13501 43612 2.196 14001 43612 2.196 14501 43607 2.196 15001 43607 2.196 15501 43610 2.196 16001 43605 2.196 16501 43605 2.196 17001 43606 2.196 17501 43605 2.196 18001 43605 2.196 18501 43604 2.196 19001 43600 2.195 19501 43603 2.196 20001 45728 2.303 20501 50706 2.553 21001 56973 2.869 21501 60628 3.053 22001 60642 3.054 22501 60640 3.054 23001 60639 3.053 23501 60643 3.054 24001 60641 3.054 24501 60642 3.054 ERR [2026-07-19 09:01:17] thinking: [not recorded in transcript] [2026-07-19 09:01:17] agent: Excellent — that's a clean result. Four stable plateaus, and the static noise is only ±3 counts. [2026-07-19 09:01:38] tool use: Write file_path: /home/agent/TE_ting/volume_knob_findings.md content: # EP-2350 volume knob — SOLVED: analog pot on GP29 / ADC3 Session date: 2026-07-19. Method: stock MicroPython v1.25.0 over the raw REPL, all digital GPIOs pulled up and change-monitored while ADC0–3 were sampled continuously (`scratchpad/knob_monitor.py`), with the user turning the knob. ## TL;DR **The volume knob is wired to the RP2350, not to the NAU88L21 codec.** It is a plain potentiometer across the 3V3 rail with its wiper on **GP29 = ADC3**. | Property | Value | |---|---| | Pin | **GP29 (ADC3)** | | Type | analog potentiometer, **not** a rotary encoder | | Range | 68 counts (0.003 V) at min → 65340 counts (3.290 V) at max | | Integral push-switch | **none** — no digital pin moved during any knob action | | Static noise | ±3 counts on a 16-sample average | ```python from machine import ADC vol = ADC(3) # GP29 level = vol.read_u16() # 0..65535, full scale usable ``` ## Evidence - A 40 s run turning the knob through its full range produced **continuous monotonic ADC3 motion across the entire 0–3.29 V span** and **zero transitions on any digital GPIO**. An encoder would have shown two pins chattering in quadrature; nothing did. - ADC0/1/2 (GP26/27/28) stayed put throughout, so only ADC3 is on the knob. - Stepped test, ~5 s per detent-free stop (raw counts, 16-sample average): ``` knob position counts volts % of full scale minimum 68 0.003 0.1 % ~25 % (by eye) 14768 0.744 22.5 % ~50 % (by eye) 43606 2.196 66.5 % ~75 % (by eye) 60641 3.054 92.5 % maximum 65340 3.290 99.7 % ``` The knob bottoms out at the rails at both ends, so the pot's wiper reaches both tracks — full-scale usable without calibration. **Taper is not established.** The mid positions were eyeballed by hand, so the deviation from linear above (22.5 / 66.5 / 92.5 vs 25 / 50 / 75) is within positioning error and cannot distinguish a linear pot from a mild audio taper. If firmware needs a true curve, mark physical detent positions and re-measure; otherwise treat the raw value as the control input and apply whatever taper you want in software. ## ⚠️ This invalidates the old "GP29 = 3V3 rail" reading `power_hold_findings.md` recorded GP29 as *"hard-tied to 3V3, not a sense line"* (float 3.290 V, pull-up 3.290 V, pull-down 3.288 V — a 0.002 V swing). That measurement was correct but was taken with **the knob at maximum**, where the wiper sits directly on the top rail through near-zero resistance. It is indistinguishable from a hard tie at that one position. The consequence matters: that document used GP29 as a **proxy for the rail /ADC VREF** when arguing that GP28's `1.630 / 3.290 = 0.4954` proves an exact 1:2 divider. **That argument is unsound** — the denominator was a volume setting, not the rail. It happened to read 3.290 V only because the knob was up. The rest of the GP28 conclusion survives on its own evidence (float 1.630 V, loaded swing 0.255 V, `R_th ≈ 4.6 kΩ`), and the two-resistor divider reading is still plausible. But GP28-vs-GP29 ratios must be recomputed against a real rail reference before being trusted. Likewise the "batteries fitted vs not" table comparing GP29 at 3.290 / 3.292 V shows only that nobody touched the knob. ## Method note Watching digital and analog simultaneously is what made this quick: one 40 s user interaction ruled out an encoder, ruled out a push-switch, and located the pot. Worth reusing for any remaining unknown control. [2026-07-19 09:01:38] tool result: Write File created successfully at: /home/agent/TE_ting/volume_knob_findings.md (file state is current in your context — no need to Read it back) [2026-07-19 09:01:41] agent: Now correcting the stale GP29 claims in the power notes. [2026-07-19 09:01:44] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/power_hold_findings.md old_string: GP29 tied to 3V3 ADC3 — hard-tied to the rail, not a sense line new_string: GP29 low impedance ADC3 — ⚠️ NOT a rail tie: this is the VOLUME POT wiper. It only looked tied to 3V3 because the knob was at max. See volume_knob_findings.md GP1,GP3,GP21 (floating here) buttons — only pulled low while pressed; see button_findings.md [2026-07-19 09:01:44] tool result: Edit The file /home/agent/TE_ting/power_hold_findings.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 09:01:49] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/power_hold_findings.md old_string: GP29 3.290 V 3.290 V 3.288 V 0.002 V hard-tied to 3V3 rail ``` **GP28 is the only genuine analog sense line.** Its ratio against the measured rail is `1.630 / 3.290 = 0.4954` — an almost exact **1:2 divider**, and new_string: GP29 3.290 V 3.290 V 3.288 V 0.002 V ⚠️ VOLUME POT at max, not the rail ``` **GP28 is the only genuine analog sense line.** Its ratio against what was assumed to be the rail is `1.630 / 3.290 = 0.4954` — an almost exact **1:2 divider**, and [2026-07-19 09:01:49] tool result: Edit The file /home/agent/TE_ting/power_hold_findings.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 09:01:54] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/power_hold_findings.md old_string: but requires an arbitrary ratio, so it is the weaker explanation. new_string: but requires an arbitrary ratio, so it is the weaker explanation. > ⚠️ **Correction (2026-07-19, later):** the ratio argument above divides by > GP29, which is **the volume pot wiper, not the rail** — it read 3.290 V only > because the knob happened to be at maximum. The `R_th ≈ 4.6 kΩ` evidence for > GP28 being a real divider still stands, but any GP28-vs-GP29 *ratio* must be > recomputed against a genuine rail reference. Same for the batteries-fitted > table below, whose "GP29 = rail/VREF" column only shows that the knob was not > touched between the two runs. See `volume_knob_findings.md`. [2026-07-19 09:01:54] tool result: Edit The file /home/agent/TE_ting/power_hold_findings.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 09:01:59] tool use: Edit replace_all: false file_path: /home/agent/TE_ting/power_hold_findings.md old_string: | Signal | GPIO | Sense | Status | |--------|-----:|-------|--------| new_string: > See also `button_findings.md` (all 5 buttons) and `volume_knob_findings.md` > (GP29 is the volume pot — this file's "GP29 tied to 3V3" is wrong; corrected > inline below). | Signal | GPIO | Sense | Status | |--------|-----:|-------|--------| [2026-07-19 09:01:59] tool result: Edit The file /home/agent/TE_ting/power_hold_findings.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 09:02:09] tool use: Write file_path: /home/agent/.claude/projects/-home-agent-TE-ting/memory/ep2350-volume-knob.md content: --- name: ep2350-volume-knob description: EP-2350 volume knob is an analog pot on GP29/ADC3 (not the codec, not an encoder) — invalidates the old "GP29 tied to 3V3" reading metadata: type: project --- EP-2350 volume knob = **plain potentiometer, wiper on GP29 / ADC3**, wired to the RP2350 (not to the NAU88L21 codec). Solved 2026-07-19. `ADC(3).read_u16()` gives 68 counts at min → 65340 at max, i.e. full scale usable, ±3 counts noise. Not a rotary encoder, and it has no integral push-switch. **Why this matters beyond the knob:** the earlier survey in `power_hold_findings.md` recorded GP29 as "hard-tied to the 3V3 rail" — that was measured with the knob at maximum, where the wiper sits on the top rail. That file then used GP29 as a **stand-in for the rail/ADC VREF** to argue GP28 is an exact 1:2 divider (`1.630/3.290 = 0.4954`). **That ratio argument is unsound**; GP28's own `R_th ≈ 4.6 kΩ` evidence still stands. Corrections are noted inline in that file and in `volume_knob_findings.md`. **How to apply:** any "pin looks hard-tied to a rail" conclusion on this board should be re-checked with the user physically moving controls — a pot at an extreme is indistinguishable from a tie. To hunt unknown controls, use `scratchpad/knob_monitor.py`, which watches all digital pins (pulled up) and all four ADCs at once, so one user interaction rules in/out encoder vs pot vs switch. Related: [[ep2350-button-map]], [[ep2350-power-latch]]. [2026-07-19 09:02:09] tool result: Write File created successfully at: /home/agent/.claude/projects/-home-agent-TE-ting/memory/ep2350-volume-knob.md [2026-07-19 09:02:13] tool use: Edit replace_all: false file_path: /home/agent/.claude/projects/-home-agent-TE-ting/memory/MEMORY.md old_string: - [EP-2350 audio tone status](ep2350-audio-tone-status.md) new_string: - [EP-2350 volume knob](ep2350-volume-knob.md) — SOLVED: analog pot on GP29/ADC3, not the codec; invalidates the old "GP29 tied to 3V3" reading and the GP28 ratio argument - [EP-2350 audio tone status](ep2350-audio-tone-status.md) [2026-07-19 09:02:13] tool result: Edit The file /home/agent/.claude/projects/-home-agent-TE-ting/memory/MEMORY.md has been updated successfully. (file state is current in your context — no need to Read it back) [2026-07-19 09:02:26] agent: The volume knob is **on the RP2350**, not the codec. **GP29 / ADC3 — a plain analog potentiometer.** Not a rotary encoder, and no integral push-switch. ```python from machine import ADC vol = ADC(3) # GP29 level = vol.read_u16() # 68 at min → 65340 at max ``` Full scale is usable without calibration — the wiper reaches both rails (0.003 V / 3.290 V), and a 16-sample average is stable to ±3 counts, so you don't need heavy filtering. **How it was ruled in:** one 40-second run watching all digital pins (pulled up) *and* all four ADCs simultaneously. Turning the knob produced continuous monotonic motion on ADC3 across the entire span with **zero** digital transitions anywhere — an encoder would have shown two pins chattering in quadrature. ADC0/1/2 stayed put. I could not pin down the **taper**. The stepped readings came out 22.5 / 66.5 / 92.5 % for eyeballed 25 / 50 / 75 % positions, which is within hand-positioning error and doesn't distinguish linear from a mild audio taper. If firmware needs the real curve, we'd want marked physical positions. Otherwise just apply whatever taper you want in software. **One important side effect — this invalidates a previous conclusion.** `power_hold_findings.md` had GP29 as "hard-tied to 3V3, not a sense line," measured as a 0.002 V swing under load. That measurement was accurate but was taken with the knob at maximum, where the wiper sits on the top rail through near-zero resistance — indistinguishable from a hard tie. That matters because the document then used GP29 as a **proxy for the rail / ADC VREF** to argue GP28 is an exact 1:2 divider (`1.630 / 3.290 = 0.4954`). The denominator was a volume setting, not the rail, so **that ratio argument doesn't hold**. GP28's independent evidence (`R_th ≈ 4.6 kΩ`, 0.255 V loaded swing) still supports a real divider, but the VBAT-vs-VBUS question now has one less piece of support than it appeared to. Similarly, the "batteries fitted vs not" table's GP29 column (3.290 vs 3.292 V) only shows nobody touched the knob. I've written `volume_knob_findings.md` and marked the corrections inline in `power_hold_findings.md` rather than deleting the old reasoning, so the trail stays visible. The broader lesson worth carrying: on this board, "pin looks tied to a rail" needs re-checking with controls physically moved.