Youry Yakimov

LPC43xx + GPDMA + SSP (burst size&)

Discussion created by Youry Yakimov on Feb 14, 2018
Latest reply on Feb 20, 2018 by Youry Yakimov

Hey, there! I have a little confusion about the stuff. I use SSP0 + GPDMA. According to CMSIS lib burst size tx is 4 bytes, burst size rx is 4 bytes too. So, there is rare occasion when tx channel (I set it to 1, for example) has finished transferring data, but rx channel (0, highest priority) doesn't. And field size in config register equals to 4 bytes. It works perfectly well if I set rx burst size to 1 byte. Also, if I manually trigger burst line for SSP0 rx FIFO those 4 bytes also come. Field size in config register is set to 0. So my question comes: which request line to DMA is used for SSP0 RX FIFO? Is it for all fifo full or single bytes, or both? Which burst size for rx must I set?

Thanks in advance!