DMA + SPI issue in LpcXprsso OM13077

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by pradeep salloju on Tue May 12 06:43:13 MST 2015

I am using LPCXpresso 54102 Evaluation board (OM13077). i have used lpcopen examples project (rom_spim_int_dma) in my application but when i am setting buffer size as BUFFSIZE 2 i am getting 4 clock cycles generating on one transaction with that i am unable to read exact slave data.
There is a problem with DMA transfer.

My application is complete synchronous application i will get valid data from slave when i push some data to it i need to write and read for each transaction DMA is required,

my intension is to send 0x15 and 0x00 only two bytes

for 0x15 response is 0x00
for 0x00 response is 0x58

but in rx buf i am not getting actual data on MISO line.

in rx buffer i am getting only


these are missing.

due to generation of extra clock on each transaction i am not getting exact data instead of i am getting some failure responses from spi slave .

And can you please tell me how to send more than 1024 bytes with DMA in spi.

Original Attachment has been moved to: logic_capture.zip

Original Attachment has been moved to: dma_spi.c.zip