MK20D classic SPI example??

terence_kong — Wed, 28 Oct 2020 22:27:19 GMT

trying to get the SPI work on K20 in order to access a flash memory.

I have checked on the scope that the SCLK did toggle during a byte send but the CS always held low.

And idea why the CS not toggling?

Is there any sample program that shows how to setup the SPI on K20?

/*******************************************************************************
* scSSP0Init - Initialize SSP0 module( we are using SSP0 module in SPI frame format
*******************************************************************************/
void scSSP0Init(void)
{

SIM_SCGC5 |= SIM_SCGC5_PORTD_MASK; //Enable PORTD
SIM_SCGC6 |= SIM_SCGC6_DSPI0_MASK; //Turn on clock to SPI0 module
/* configure GPIO for SPI0 function */
PORTD_PCR1 = PORT_PCR_MUX(2); //SPI0_CLK
PORTD_PCR2 = PORT_PCR_MUX(2); //SPI0_SO
PORTD_PCR3 = PORT_PCR_MUX(2); //SPI0_SI
PORTD_PCR4 = PORT_PCR_MUX(2); //SPI0_CS1
GPIOD_PDDR |= (1<<SPI_DFLASH_CS_PIN); //Set PTD4 as output
GPIOD_PSOR |= (1<<SPI_DFLASH_CS_PIN); //Set High iniitializlly

SPI0_MCR |= SPI_MCR_MDIS_MASK | SPI_MCR_HALT_MASK; // Allows external logic to disable DSPI clock, halt DSPI transfer
//SPI0_MCR |= SPI_MCR_DIS_TXF_MASK | SPI_MCR_DIS_RXF_MASK; // Disable RX and TX DSPIFIFO as simplified double buffered SPI
SPI0_CTAR0 = 0x38010008; //8 bit per frame, 50/50 duty, BR scaler = 256, BR div = 3, ~130kbps
SPI0_MCR |= SPI_MCR_MSTR_MASK; //Master mmode
//SPI0_TCR = (uint32_t)0x00UL; //Clear transfer count
// SPI0_RSER = (uint32_t)0x00UL; //Disable Interrupt and DMA
//SPI0_SR = SPI_SR_EOQF_MASK | SPI_SR_TCF_MASK | SPI_SR_RFOF_MASK | SPI_SR_TFUF_MASK | SPI_SR_TFFF_MASK | SPI_SR_RFDF_MASK; //Clear Status Register
SPI0_MCR &= ~(SPI_MCR_MDIS_MASK | SPI_MCR_HALT_MASK); // Enable DSPI clock, start DSPI transfer
//SPI0_MCR |= SPI_MCR_DIS_TXF_MASK | SPI_MCR_DIS_RXF_MASK; // Disable RX and TX DSPIFIFO as simplified double buffered SPI
}

/*******************************************************************************
* SPI Receive Byte, receive one byte only, returns Data byte
*******************************************************************************/
unsigned char SSP0ReceiveByte( void )
{
unsigned char rxData= 0xff;
SPI0_SR |= SPI_SR_TCF_MASK; //clear transfer
//SPI0_PUSHR = 0xFF;
// Wait until the Busy bit is cleared
if (!SSP0WaitReady())
{
return rxData;
}
rxData = SPI0_POPR;
return rxData;
}

/*******************************************************************************
* SSP0 SendByte, send one byte to EEPROM
*******************************************************************************/
void SSP0SendByte(unsigned char SP0Byte)
{
SPI0_SR |= SPI_SR_TCF_MASK; //clear transfer
SPI0_PUSHR = SP0Byte; //PUSH TX FIFO
// Wait until the Busy bit is cleared
if (!SSP0WaitReady())
{
return;
}
}

Re: MK20D classic SPI example??

nxf56274 — Thu, 29 Oct 2020 00:57:43 GMT

Hi,

You configure the PTD4 as CS. So you can't configure PDDR and PSOR except you configure the pin as gpio. You can download the sample in https://mcuxpresso.nxp.com/en/select.

K20 has same content as k60. So k20 uses k60's sample. You can refer it.

Have a great day,
TIC

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MK20D classic SPI example??

Re: MK20D classic SPI example??