Joe Gibson

differences between spi on mc9s256a and mc9s256cfu ?

Discussion created by Joe Gibson on Sep 26, 2007
Latest reply on Oct 4, 2007 by Daniel Lundin
the problem began when the mc9s256a (bat wing logo) was discontuined and i started using the mc9s256cfu part (new freescale logo). i have cpu's running on a single spi bus. all cpu are slaves except when changed to master to speek to other cpu's. this is a polled system with each cpu addressed. the only way i can get the mc9s256cfu to receive data is to invert both cpol and cpha when setting up slave. in testing i install 256a and it works, same board with 256cfu and will not work. then i clear cpol, and cpha bits and the 256cfu then works. no other changes are made to the other cpu's on the buss.