Hi, I'm working with a LPC1758 processor and an AT45 dataflash. The dataflash communicate with the processor by SSP1 and dma.
In my first attempt: I want to read the status register from the dataflash. The specific command is a single byte 0xD7 - no addr bytes or dummy bytes have to be transmitted to the dataflash.
I setup the corresponding tx dma channel
#define tx_datasize 1 /* at45-command-size */ pHw->DMACCControl = (tx_datasize & 0x0FFF)|(0x00 << 12) |(0x00 << 15)|(0x00 << 18)|(0x00 << 21)|(1 << 26)|0x80000000;
and start the transfer.
Unfortunately the dma interrupt handler isn't called. The error seems to be due to the "tx_datasize". If I set the "tx_datasize" to 2 the dma interrupt handler is called.
I couldn't find any information in the user manual that told me that I've to increase the tx_datasize....
best regards Lars
I think the burst size and transfer width settings are not correct - maybe someone else could help you further; cause I didn't know it by heart... but that could be the problem to your description...