change i2c speed on metro m4 express

[dheijl]

Hi,

I use the Metro M4 Express to control stepper motors with Motor Shields V2, using the Arduino IDE. I like those SAMD51 boards!
But... I need to increase the i2c speed.
The recommended change in the docs is for Atmel based boards only, and I can't find the equivalent for the SAMD51 boards (I don't want to change the SAMD51 twi code).
So, I would need the SAMD51 equivalent of:

Code: Select all

TWBR = ((CPU_FREQ / 400000L) - 16) / 2;

Thanks!

[dheijl]

To answer my own question: after looking at the library source code I noticed that the i2c used by the M4 Metro is Wire.
So the following line does the trick to get a higher RPM out of the steppers:

Code: Select all

Wire.setSpeed(400000);

[dheijl]

The motor shield also support "fast plus" i2c speed (1000000) because the PCA9685 chip does.