chaalar wrote on Thursday, April 03, 2008:
A1) You don’t need to use PDC, but it is easier and more CPU friendly.
A2) The difference is that you don’t need ISR for the PDC that much. You
will probably want to know end of transfer so you will only handle PDC related
ENDTx or ENDRX flag in the ISR for the PDC. For the other case, you will need to
handle many more flags in the interrupt handler.
A3) There are some example codes posted to this forum(or to theAT91SAM yahoogroup)
If you are asking for a complete freeRTOS driver, then you have to do it yourself.
I have never seen any. But mechanism is similar for any driver.
For example you can take a serial driver as basis and replace usart related calls with
the spi ones.