Flipsky 75100 — can LispBM actually receive custom data from an ESP32 over UART? event-data-rx never fires

[Philippe Larouche]

Hi all,

I reflashed my Flipsky 75100 (alu) from the wrong 75_300_R2 firmware to the correct 75_100_V2 (FW 6.06). Motor, throttle and brakes all work great now.

What I'm stuck on: I want a LispBM script to read a couple of bytes (drive mode + key on/off) from an ESP32 wired to the COMM port. I send standard COMM_CUSTOM_APP_DATA (cmd 36) packets and listen with the event-data-rx handler straight from the docs. event-data-rx never fires. The handler thread runs, event-enable is set, but nothing ever arrives — even a catch-all branch in the recv never triggers.

Stuff I've already checked:

• The link works both ways — a COMM_FW_VERSION request from the ESP gets a full reply, so wiring/baud/pins are fine.
• The ESP is definitely sending valid cmd-36 packets (verified byte-by-byte, CRC is correct).
• App = ADC and UART, 115200, matches the ESP.
• A minimal copy-from-the-docs handler fails the same way.
• Same behavior before and after the firmware fix.

I also tried raw uart-start + uart-read-bytes (App set to NONE to free the port) and got zero bytes, even though the ESP is sending.

One thing left: VESC Tool still says "limited mode" (my tool version vs the 6.06 firmware). I found an old thread where that stopped events from firing — could that be the cause?

Questions:

• Is event-data-rx supposed to fire from a plain external MCU sending cmd 36 over the COMM UART, or only from VESC Tool?
• On the 75100, is the COMM port (RX/TX) the UART that LispBM actually sees, or is it the second UART (RX2)?
• Has anyone gotten an external-MCU → LispBM data path working on a Flipsky board?

Thanks — been stuck on this for a while.