Hello,
for an LED related application using the arduino DUE, i need an SPI transmission rate of about 5mbps (5 mega bit per second). If possible, I would like to use the USART1 in SPI mode, with DMA (the native SPI port is already driving an SD card reader, and the LED hardware does not have a select logic, hence the USART1 approach). I'd be happy if someone could point out (apart from the SAM3X data sheet) how to start. Thanks!
ps: with pure bit-banging using direct port access in C (not asm) I can only achieve 1.5mbps, which means I need (averaged over all the loop logic etc. which is necessary to shift out the data manually) 63 clock cycles per bit, which seems to be about right.