Can't read or write any TWI registers after moving to the app_twi library

RE: Can't read or write any TWI registers after moving to the app_twi library

Eliot Stock — Sat, 04 Jun 2016 12:39:09 GMT

This was down to me calling app_twi_perform() and passing 1 as the number of transfers. Because of that confusing "write before read" idiom with I2C, it's actually two transfers, one for the write and one for the read. Best explained here for anyone struggling with the same issue:

www.robot-electronics.co.uk/i2c-tutorial

RE: Can't read or write any TWI registers after moving to the app_twi library

Eliot Stock — Sat, 04 Jun 2016 11:22:58 GMT

@Ole Bauck Thanks. Have fixed that, but there must be something else. New code attached above.

RE: Can't read or write any TWI registers after moving to the app_twi library

Ole Bauck — Fri, 03 Jun 2016 11:01:54 GMT

I would define the transfer as static or else it is placed on the stack and destroyed when the function exits, I think that is what is causing your problems. App_twi_perform() will call app_twi_schedule().