CCS/TM4C129ENCPDT: SPI Program for multiple slave

Tool/software: Code Composer Studio

Hi,

In my design I have to configure 2 slave modules in SPI2.

The slave module i used is TI- AMC7820.

First i tried to configure single SPI module.

The Pins I used was PD0,PD1 and PD3. The chip select was PK3 for slave 1.

I have modified the code for write 0x2345 to a register and read back it. But what I read back is NULL

The init,read and write functions are as below.

void SSI2Init(void) //SPI 2 initialization
{

//
// The SSI2 peripheral must be enabled for use.
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI2);


SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);


SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOK);//  CS1 K3

//
// Configure the pin muxing for SSI0 functions on port D0, D1, and D3.
//
GPIOPinConfigure(GPIO_PD0_SSI2XDAT1);
GPIOPinConfigure(GPIO_PD1_SSI2XDAT0);
GPIOPinConfigure(GPIO_PD3_SSI2CLK);



// GPIOPinConfigure(GPIO_PA3_SSI0FSS);// This is not done as CS is a GPIO pin



GPIOPinTypeGPIOOutput(GPIO_PORTK_BASE, GPIO_PIN_3);//  CS1 for slave 1 as GPIO output pin

    GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_3,GPIO_PIN_3);//make it high, as it is active low

//
// Configure the GPIO settings for the SSI pins.
//

GPIOPinTypeSSI(GPIO_PORTD_BASE, GPIO_PIN_3 | GPIO_PIN_1 | GPIO_PIN_0);
//
// Configure and enable the SSI port for SPI master mode. Use SSI2,
//

SSIConfigSetExpClk(SSI2_BASE, g_ui32SysClock, SSI_FRF_TI,
SSI_MODE_MASTER, 1000000, 8);


//
// Enable the SSI2 module.
//
SSIEnable(SSI2_BASE);

//
// Read any residual data from the SSI port.
//
while(SSIDataGetNonBlocking(SSI2_BASE, &pui32DataRx[0]))
{
}

}

void SPI2Read(void)
{

pui32DataTx[0]=0x82;// for reading from register

pui32DataTx[1]=0x40;

GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_3 ,0);// CS LOw; AMC expects Active low control signal
for(ui32Index = 0; ui32Index < 2; ui32Index++)
{
//
// Send the data using the "blocking" put function. This function
// will wait until there is room in the send FIFO before returning.
// This allows you to assure that all the data you send makes it into
// the send FIFO.
//
SSIDataPut(SSI2_BASE, pui32DataTx[ui32Index]);
}

//
// Wait until SSI0 is done transferring all the data in the transmit FIFO.
//
while(SSIBusy(SSI2_BASE))
{
}



// Receive 2 bytes of data.
//
for(ui32Index = 0; ui32Index < 2; ui32Index++)
{


//
// Receive the data using the "blocking" Get function. This function
// will wait until there is data in the receive FIFO before returning.
//
SSIDataGet(SPIBase, &pui32DataRx[ui32Index]);

// Since we are using 8-bit data, mask off the MSB.
//
pui32DataRx[ui32Index] &= 0x00FF;


}
GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_3 ,GPIO_PIN_3 );// Reset CS to High

}

void SPIwrite(void)
{

pui32DataTx[0]=0x02;
pui32DataTx[1]=0x40;
pui32DataTx[2]=0x23;
pui32DataTx[3]=0x45;


GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_3 ,0)// CS LOw; AMC expects Active low control signal
for(ui32Index = 0; ui32Index < 4; ui32Index++)
{


//
// Send the data using the "blocking" put function. This function
// will wait until there is room in the send FIFO before returning.
// This allows you to assure that all the data you send makes it into
// the send FIFO.
//
SSIDataPut(SSI2_BASE, pui32DataTx[ui32Index]);


}

//
// Wait until SSI0 is done transferring all the data in the transmit FIFO.
//
while(SSIBusy(SSI2_BASE))
{
}
GPIOPinWrite(GPIO_PORTK_BASE, GPIO_PIN_3 ,GPIO_PIN_3 );// Reset CS to High

}

Please Help me.

Thanks in advance.