Lars provided a skeleton program for single byte transfer using hardware control (CTRLB.MSSEN = 1), it works correctly
I'm still fighting a program which should control a MAX7219 8-digit 7-segment LED display driver
This needs 3 signals, slave select (SS), serial data out (MOSI), serial clock (SCK).
At the start SS = 1 and CTRLB.MSSEN = 0
The required operations are:
1. Set SS = 0 using program control
2. Transmit the first byte, these are shifted into the MAX7219 shift register
3. Transmit the second byte, these are then in the shift register
4. Set SS = 1, the MAX7219 loads the16 bits in the shift register
It's not possible to use hardware control of the SS line because one has to transmit two bytes, then raise SS
The SCK signal does not appear, although in Lars' program it does.
The SS signal and MOSI signals are as expected.
Can anyone tell me how to make the SCK clock signal visible?
Many thanks for suggestions
Best wishes, Jerry