Hi guys may I ask what is the maximum allowed speed for the SPI of the master MCU.
I connected 2 MCUs with the master as ATMEGA2560 and slave as ATMEGA 328P. The master has 16MHz clock frequency while the slave has 1MHz clock frequency. Initially I set SPR0 to divide fosc with 16 to set the master clock. Then I found out it is not working so I tried to change the divider to 128. After that I got a good result. May I ask what are considerations in setting the clock divider. Thank you.