Kinetis Controller Not Replying Properly in SPI Slave Mode

[waqasbutt]

Hello,

I am using K20 series controller. In slave mode the controller keeps sending the first value that has been pushed through PUSHR_SLAVE. It never updates.

The slave is receiving data correctly which can be seen through the oscilloscope. The settings CPHA and CPOL also match in slave and master

Images of Oscilloscope

1. Yellow (Clk)

2. Blue    (Slave Out)

3. Purple (Master Out)

4. Green (Chip Select)

Slave Code is as follows

SLAVE:

// Initialization
void SPI1_Init(void)
{
 /* SIM_SCGC6: DSPI1=1 */
 SIM_SCGC6 |= SIM_SCGC6_DSPI1_MASK;
 /* SPI1_MCR: MSTR=0,CONT_SCKE=0,DCONF=0,FRZ=0,MTFE=0,PCSSE=0,ROOE=0,??=0,??=0,PCSIS=0,DOZE=0,MDIS=0,DIS_TXF=0,DIS_RXF=0,CLR_TXF=0,CLR_RXF=0,SMPL_PT=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,HALT=1 */
 SPI1_MCR = SPI_MCR_DCONF(0x00) |
 SPI_MCR_PCSIS(0x00) |
 SPI_MCR_SMPL_PT(0x00) |
 SPI_MCR_HALT_MASK;
 /* SPI1_MCR: MSTR=0,CONT_SCKE=0,DCONF=0,FRZ=0,MTFE=0,PCSSE=0,ROOE=0,??=0,??=0,PCSIS=0x0F,DOZE=0,MDIS=0,DIS_TXF=1,DIS_RXF=1,CLR_TXF=1,CLR_RXF=1,SMPL_PT=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,HALT=1 */
 SPI1_MCR = SPI_MCR_DCONF(0x00) |
 SPI_MCR_PCSIS(0x0F) |
 SPI_MCR_DIS_TXF_MASK |
 SPI_MCR_DIS_RXF_MASK |
 SPI_MCR_CLR_TXF_MASK |
 SPI_MCR_CLR_RXF_MASK |
 SPI_MCR_SMPL_PT(0x00) |
 SPI_MCR_HALT_MASK;
 /* SPI1_TCR: SPI_TCNT=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
 SPI1_TCR = SPI_TCR_SPI_TCNT(0x00);
 /* SPI1_CTAR1: DBR=0,FMSZ=0x0F,CPOL=0,CPHA=0,LSBFE=0,PCSSCK=0,PASC=0,PDT=0,PBR=0,CSSCK=0,ASC=0,DT=0,BR=0 */
 SPI1_CTAR1 = SPI_CTAR_FMSZ(0x0F) |
 SPI_CTAR_PCSSCK(0x00) |
 SPI_CTAR_PASC(0x00) |
 SPI_CTAR_PDT(0x00) |
 SPI_CTAR_PBR(0x00) |
 SPI_CTAR_CSSCK(0x00) |
 SPI_CTAR_ASC(0x00) |
 SPI_CTAR_DT(0x00) |
 SPI_CTAR_BR(0x00);
 /* SPI1_CTAR0_SLAVE: FMSZ=7,CPOL=0,CPHA=0 */
 SPI1_CTAR0_SLAVE = (uint32_t)((SPI1_CTAR0_SLAVE & (uint32_t)~(uint32_t)(
 SPI_CTAR_SLAVE_FMSZ(0x18) |
 SPI_CTAR_SLAVE_CPOL_MASK |
 SPI_CTAR_SLAVE_CPHA_MASK
 )) | (uint32_t)(
 SPI_CTAR_SLAVE_FMSZ(0x07)
 ));
 /* SPI1_SR: TCF=1,TXRXS=1,??=0,EOQF=1,TFUF=1,??=0,TFFF=1,??=0,??=0,??=0,??=0,??=0,RFOF=1,??=0,RFDF=1,??=0,TXCTR=0,TXNXTPTR=0,RXCTR=0,POPNXTPTR=0 */
 SPI1_SR = SPI_SR_TCF_MASK |
 SPI_SR_TXRXS_MASK |
 SPI_SR_EOQF_MASK |
 SPI_SR_TFUF_MASK |
 SPI_SR_TFFF_MASK |
 SPI_SR_RFOF_MASK |
 SPI_SR_RFDF_MASK |
 SPI_SR_TXCTR(0x00) |
 SPI_SR_TXNXTPTR(0x00) |
 SPI_SR_RXCTR(0x00) |
 SPI_SR_POPNXTPTR(0x00);
 /* SPI1_RSER: TCF_RE=0,??=0,??=0,EOQF_RE=0,TFUF_RE=0,??=0,TFFF_RE=0,TFFF_DIRS=0,??=0,??=0,??=0,??=0,RFOF_RE=0,??=0,RFDF_RE=1,RFDF_DIRS=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
 SPI1_RSER = SPI_RSER_RFDF_RE_MASK;
 /* SPI1_MCR: HALT=0 */
 SPI1_MCR &= (uint32_t)~(uint32_t)(SPI_MCR_HALT_MASK);
}


// Service Routine
PE_ISR(INT_SPI1_HANDLER)
{
    uint32_t receivedValue = SPI1_POPR;
    uint8_t valueToSend = 0;

   SPI1_SR = SPI_SR_RFDF_MASK | SPI_SR_TCF_MASK;
    if(receivedValue == 0x81)
       valueToSend = 0xF0;
    else
       valueToSend = 0x0F;
   while((SPI1_SR & SPI_SR_TFFF_MASK)==0);
   SPI1_PUSHR_SLAVE = valueToSend;
}

[waqasbutt · Accepted solution]

Problem solved.

It was a hardware problem. cs pin was not correctly attached