calcprogrammer1 / stepper-motor-controller Goto Github PK

Is it possible to use your slave library to send data from slave to master?

Thanks for the USI I2C library, great help. However, I found when in USI I2C Slave mode that if your Microcontroller is running at 8MHz or lower you will need to reduce the Arduino's Wire Library default (100kHz) I2C SCL frequency. Else the timing in the ACK section can be a bit dicey.

To change the Arduino's Wire Library default I2C SCL frequency you need to call Wire.setClock(<SCL_FREQ>) where SCL_FREQ is anywhere between 31000L to 400000L (31kHz to 400kHz). See begin section here .

This was an extremely annoying bug to hunt down.

Hope this makes sense and helps others.

There is an error with a slave sending multiple data bytes. Either need to clear the USIDR register within the state = USI_SLAVE_SEND_DATA_ACK_WAIT or change line 206 to be if(USIDR & 0x01).

I used the usi_i2c_slave.c and usi_i2c_slave.h files, in fact I needed to change the line 162 in usi_i2c_slave.c from "USI_Slave_internal_address_set = 0;" to "USI_Slave_internal_address_set = 1;".