Has somebody ever used SSP0 with DMA ?
I'm starting with a demo code from NXP, but this code is very light. It seems to be hard to manually do the 'chip select' at the right time and yet, I'm just trying to read my slave's status register !
Thanks for any help.
Now I can write and read a byte through DMA. Transmit looks good, even for a lot of bytes. But I have an issue concerning the reception. Data are ok on the SSP0 peripheral but what I find in the FIFO is what I've sent (I checked the registers). It look likes it read the SSP0 register too early (the rigth data hasn't come yet).
I tried to use peripheral as 'flow controller' but nothing is working.
As I've said, writing the 'read status register' command and getting the status value is ok .
I don't understand how can I manage the reading synchronisation...
Thanks for any help
Ok, now I can use DMA with SSP0 without any problem at 18MHz and with burst size on the SSP0 side up to 4 bytes. But I have 2 questions.
First, what's the faster working GPDMA clock ?
My code is working at 18MHz but when I try 36MHz I can see the same value is read two times (as if the clock was too fast against the SSPO Rx). But it is supposed to be drived by the interrupt so I don't understand. My slave can work up to 70MHz.
Then, as I have said, I'm using the DMA channel with a dest busrt (SSP0 Tx) and a source burst (SSP0 Rx) of 4 bytes (bit 12 to bit 17 of DMACC0Control register on lpc23xx). The "8 bytes" configuration is not working but it should because the SSP0 fifo is up to 8 bytes.
Thanks in advance for any help.