2nd I2C on ATMega328PB handled different to Arduino IDE defaults !?

[Balze2]

Hi MCUdude,

for some time I try to get the second I2C bus from the ATMega328PB working with display libraries (I.e. U8G2) I only get it working with a workaround. It seems, that it's not working, because your core handles the second I2C different from the Arduino defaults.

A discussion with the developer of U8G2 showed, that his library needs a define of WIRE_INTERFACES_COUNT >= 2 to be able to work with another than the first I2C. This value does not exist in your core (At least I wasn't able to find it. :)

The "Arduino Zero" is one of the few Microcontrollers with more than one I2C and official support. (Imho)

In the variants.h there is a define for the number of I2Cs. The generation of Wire instances is different to your solution too. Please have a look at wire.h and wire.cpp

wire.h `#if WIRE_INTERFACES_COUNT > 0 extern arduino::TwoWire Wire;

endif

if WIRE_INTERFACES_COUNT > 1

extern arduino::TwoWire Wire1;

endif

if WIRE_INTERFACES_COUNT > 2

extern arduino::TwoWire Wire2; ... ...`

wire.cpp `#if WIRE_INTERFACES_COUNT > 1 arduino::TwoWire Wire1(&PERIPH_WIRE1, PIN_WIRE1_SDA, PIN_WIRE1_SCL); void WIRE1_IT_HANDLER(void) { Wire1.onService(); }

endif

if WIRE_INTERFACES_COUNT > 2

arduino::TwoWire Wire2(&PERIPH_WIRE2, PIN_WIRE2_SDA, PIN_WIRE2_SCL); void WIRE2_IT_HANDLER(void) { Wire2.onService(); }

endif

... ...`

Maybe it's an option to adapt this "Arduino - standard"?!

Thank you very much for your effort.

Best regards

Rainer

[MCUdude]

Hi!

Are you able to use the second i2c port (Wire1) on ATmega328PB with u8g2 if you add #define WIRE_INTERFACES_COUNT 2 to pins_arduino.h?

[Balze2]

Hi,

good idea. Didn't try it yet. 🤣 I'll try in the evening, when I'm back home.

[Balze2]

Thank you very much for your hint!

That simple... shame on me 😄

I added #define WIRE_INTERFACES_COUNT 2 to the pins_arduino.h in the variants folder of the MiniCore. And added #include <wire1.h> to theU8G2 "hello world" Example

Now it's working!

Thanks and best regards

Balze

[MCUdude]

Thanks for testing! I'll add #define WIRE_INTERFACES_COUNT 2 to pins_arduino.h then.

Thanks for reporting!

[Balze2]

Thank you for taking care!

It's not necessary to include wire1.h! This is obviously done by dependecies.