Processor Expert SoftwareのトピックRe: Kinetis DMA & SPI

Kinetis DMA & SPI

mntmrk — Wed, 01 Feb 2012 17:41:58 GMT

Hi,

I need to use link SPI with DMA.

I'm novice of PE, and I try to configure DMA and SPI but I don't find the right way to do it.

Please post me some usefull suggestion.....

Re: Kinetis DMA & SPI

ProcessorExpert — Fri, 03 Feb 2012 20:54:15 GMT

Hi,

could you be more specific what for and how do you need to use the SPI ?

What Kinetis derivative are you using ?

best regards
Petr Hradsky
Processor Expert Support and Servicepacks Team

Re: Kinetis DMA & SPI

mntmrk — Fri, 03 Feb 2012 21:48:41 GMT

Hi,

I have to send a array of byte to led matrix using DMA.

The size of the buffer is from 10 up to 1024 byte

I'm working with K20N512VL processor. CW is 10.1

regards,

Mirko

Re: Kinetis DMA & SPI

ProcessorExpert — Tue, 07 Feb 2012 22:38:17 GMT

Hi,

The SPIMaster_LDD component does not support DMA transfer so it's necessary to use peripheral initialization component Init_SPI and a component for setting up DMA transfer. It can be either Init_DMA or DMA_LDD accompanied with DMA_Transfer.

Unfortunatelly, we don't have a specific example for SPI, however, there is an example of DMA configuration in the help of the DMA_Transfer component (use Help on component pop-up menu commend for the component) in the section Typical usage. One of the examples on that page is '2- Memory-to-peripheral device nested transfers...' intended to be used with DAC paripheral.

best regards
Petr Hradsky
Processor Expert Support Team

Re: Kinetis DMA & SPI

japex92 — Sat, 29 Dec 2012 05:08:10 GMT

Hello ProcessorExpert

I am writing to know exactly how the DSPI bean works on the PE for the kinetis family (k53 and K60 to be precise). I have

followed a tutorial from freescale (Freescale Technical Information Center) and got the TX working properly; but I still don't get how TX and RX are set independently if the protocol is achieved by shifting the registers involved in the communication. I did activate the events related to SPI SM1_ReceiveBlock and SM1_SendBlock, but dont know how to syncronize both if I have to receive data while it's transmiting.

I have also tried this on other code:

#define READ_SPI_FLASH_DATA() (unsigned char)SPI2_POPR

#define WAIT_SPI_RECEPTION_END() while (!(SPI2_SR & SPI_SR_RFDF)) {}

#define CLEAR_RECEPTION_FLAG() SPI2_SR |= SPI_SR_RFDF

#define WRITE_SPI_CMD0_LAST(byte) SPI2_PUSHR = (byte | SPI_PUSHR_EOQ | ulChipSelectLine | SPI_PUSHR_CTAS_CTAR0) // write final byte to output FIFO - this will negate the CS line when complete

WRITE_SPI_CMD0(0xff); // write dummy

while( SPI_SR_EOQF != (SPI2_SR & SPI_SR_EOQF));

SPI2_SR = SPI2_SR | SPI_SR_EOQF | SPI_SR_TCF ;

SPI2_MCR |= 0xC01; // halt = 1

WAIT_SPI_RECEPTION_END(); // wait until at least one byte is in the receive FIFO

(void)READ_SPI_FLASH_DATA(); // discard

CLEAR_RECEPTION_FLAG(); // clear the receive flag

Please advise me what to do and how to read the RX buffer when transfering data bytes.

Cheers,