I´ve just soldered a small project for myself, and i´ve just encountered some issues.
Due to the general unavailability of most MCUs, I´ve chosen the Atmega32U2, because for my application, its more the sufficient.
Is there any way to get PIO and this mcu working together, or do I have to change the MCU
Well in the standard way, when just using a e.g. ATMega32U4 board and changing the MCU field to U2, you’ll get lots of compiler errors everywhere where GPIO pins or registers are referenced that the U2 does not have.
avr-gcc -o .pio\build\leonardo\FrameworkArduino\wiring_digital.c.o -c -std=gnu11 -fno-fat-lto-objects -Os -Wall -ffunction-sections -fdata-sections -flto -mmcu=atmega32u2 -DPLATFORMIO=50300 -DARDUINO_AVR_LEONARDO -DF_CPU=16000000L -DARDUINO_ARCH_AVR -DARDUINO=10808 -DUSB_VID=0x2341 -DUSB_PID=0x8036 "-DUSB_PRODUCT=\"Arduino Leonardo\"" -DUSB_MANUFACTURER=\"Arduino\" -IC:\Users\Max\.platformio\packages\framework-arduino-avr\cores\arduino -IC:\Users\Max\.platformio\packages\framework-arduino-avr\variants\leonardo C:\Users\Max\.platformio\packages\framework-arduino-avr\cores\arduino\wiring_digital.c
In file included from C:\Users\Max\.platformio\packages\framework-arduino-avr\cores\arduino\Arduino.h:258:0,
C:\Users\Max\.platformio\packages\framework-arduino-avr\variants\leonardo/pins_arduino.h:213:14: error: 'DDRE' undeclared here (not in a function); did you mean 'DDRB'?
C:\Users\Max\.platformio\packages\framework-arduino-avr\variants\leonardo/pins_arduino.h:214:14: error: 'DDRF' undeclared here (not in a function); did you mean 'DDRE'?
You can ‘fix’ those by using a new variant based on the e.g. Leonardo but removing every reference to the non-existing pins.
There may be a possibility that regular firmwares compiled for a U4 work, provided you never use a register that the U2 does not physically have (and all registers are at the same place). I have not tried this.
Thanks for your awesome help
I wasn´t aware that it´s done in this way, but i´ll try my best to understand it
Actually I´m trying get the Pinmapping right, but there is something I dont get : I´ve used PortC5 in my Schematic, but i can´t find any reference to it in the pins_arduino.h .
What do I have to do that I can adress that Pin and how can I make sure that the other Pins I found are logically connected to the right pin ?
There are two critical arrays for the pin mapping:
Imagine a list of Arduino pin numbers, 0 (meaning ‘D0’) to say, 30, (meaning D30). And lets say we decide that Arduino pin 0 is “PD2”. Then the first array, digital_pin_to_port_PGM, would have at the 0th (= arduino pin number) /first index the value PD, and the second array, digital_pin_to_bit_mask_PGM, would have the value _BV(2) (the macro is “bit value” and evaluates _BV(n) = 1 << n). To set the pin “D1” to e.g. PC5, we would write PC as the second element (index = 1) in the first array, and in the second array’s second element to _BV(5).
So what you could do is add D31 as a new pin and add the above mentioned values to the arrays, then refer to your pin as number 31. (pinMode(31, OUTPUT);) etc. to control the therefore mapped PC5 pin.