Is it possible to program the GPy without the expansion board?



  • It's my first time with GPy and Pycom in general. I didn't purchase the expansion board because I was hoping I could just build my own PCB with a USB port and power connections to which I can latch the GPy. Like I've done with other microcontrollers before.
    But I didn't come across any documentation where they've tried programming without the expansion board. Is there anyone else going ahead with their own PCBs?





  • @Dinali_S Doing that is pretty easy. Powering is by Vin and GND. The Range for Vin is 3.4V - 5.5V.
    Communication is though P0 (RX), P1 (RX) and P2 (Boot mode). P0 and P1 is a normal UART link at 3.3 V ('TTL') levels, 115200 Baud for REPL, higher speed for firmware uploads. P2 will be tested by the ESP32 bootloader at the time of reset. If it is Low, then the device enters bootloader mode, and you can upload a firmware though P0 and P1 with esptool.py. If P2 is high at reset time, then the device runs the firmware.
    Usually, people use a standard USB/UART adapter for communication with the module. But you can also use legacy com port, if you add a transceiver in between to transfer between RS232 (-12v/+12v) and 'TTL' (+3.3V/0V) signal levels.
    P.S.: I quote 'TTL', because that used to be 0 and 5V levels, whereas the ESP32 uses 0 and 3.3V levels.


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