DigiSpark compilation failure using CDC library

PlatformIO Core
2

Here’s how to get it to work.

  • edit /Users/krupagj/.platformio/packages/framework-arduino-avr-digistump/libraries/DigisparkCDC/DigiCDC.cpp line 211, change char into unsigned char (fixes "narrowing int to [signed] char error)
  • edit /Users/krupagj/.platformio/packages/framework-arduino-avr-digistump/libraries/DigisparkCDC/usbdrvasm.asm and remove or comment out the end statement
  • fix your main.cpp code by replacing it with this
#include <DigiCDC.h>

extern "C" void setup() {
  SerialUSB.begin();
}

 extern "C" void loop() {
  SerialUSB.println("Hello world");
  SerialUSB.delay(1000);
}
  • because setup() and loop() need to use C-linkage to be able to be found by the startup.c code. also the header file for DigiCDC does declare the existence of a begin(unsigned long) function, but it’s not implemented, so calling it will results in a function not defined error. (Also, a baudrate for a USB CDC is pointless)

You should then see

Building .pio\build\digispark-tiny\firmware.hex
Advanced Memory Usage is available via "PlatformIO Home > Project Inspect"
RAM:   [====      ]  43.0% (used 220 bytes from 512 bytes)
Flash: [=====     ]  54.1% (used 3252 bytes from 6012 bytes)

There are still however a lot of warnings regarding the re-definition of the BIN macro (e.g. used in Serial.println(value, BIN); by the original Atmel device header. So I’m not sure if that’s going to work and you shouldn’t use it probably.

The USB D+ and D- pins seem to be port B pins 4 and 3 if I read DigiCDCDevice::usbBegin() correctly. Since I don’t have the board I have no idea if it’s going to work.

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