MSP432E401Y: MSP432E401Y with MAX31855 (Read only Mode 1 SPI Interface)

Hi Chris,
Thanks. I got it working by using a similar approach to what i used for the MSP432P. Including my code and hope others might find it useful.

My functions used are:

void configure_SPI_SSI3(void)
and
void MAX31855ReadTemperature(void)

/*
*
* void configure_SPI_SSI3(void)
*
* SSI3 used: SCLK = PQ0, MOSI = PQ2 MISO = PQ3
* GPIO pin PQ1 will be used as CS
*
* The only connections to the MAX31855 chip are PQ0, PQ1 and PQ2
*/

void configure_SPI_SSI3(void)
{
uint32_t getSPIResponseData;

// Enable clocks to GPIO Port Q and configure pins as SSI
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOQ);
while(!(MAP_SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOQ)))
{
}

// Configure pins as SSI
MAP_GPIOPinConfigure(GPIO_PQ0_SSI3CLK); // CLK
// MAP_GPIOPinConfigure(GPIO_PQ1_SSI3FSS); // CS
MAP_GPIOPinConfigure(GPIO_PQ2_SSI3XDAT0); // MOSI
MAP_GPIOPinConfigure(GPIO_PQ3_SSI3XDAT1); // MISO
MAP_GPIOPinTypeSSI(GPIO_PORTQ_BASE, (GPIO_PIN_0 | GPIO_PIN_2 | GPIO_PIN_3));


// Configure the PQ1 as a GPIO output and set high
MAP_GPIOPinTypeGPIOOutput(GPIO_PORTQ_BASE, GPIO_PIN_1);
// MAP_GPIOPinWrite(GPIO_PORTQ_BASE, GPIO_PIN_1, GPIO_PIN_1);


// Enable the clock to SSI-3 module and configure the SSI Master
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI3);
while(!(MAP_SysCtlPeripheralReady(SYSCTL_PERIPH_SSI3)))
{
}

MAP_SSIConfigSetExpClk(SSI3_BASE,
getSystemClock,
SSI_FRF_MOTO_MODE_1,
SSI_MODE_MASTER,
(getSystemClock/30), // 4Mhz Clock frequency to SSI module, should be >= 2* bit rate (master mode) OR 12*bit rate (slave mode)
8); // 8-bit data

MAP_SSIEnable(SSI3_BASE);

MAP_GPIOPinWrite(GPIO_PORTQ_BASE, GPIO_PIN_1, GPIO_PIN_1);

/* Flush the Receive FIFO */
while(MAP_SSIDataGetNonBlocking(SSI3_BASE, &getSPIResponseData));

}


/*
*
* void MAX31855ReadTemperature(void)
*
* Read MAX31855 and store values in struct MAX31855 MAX31855Sensor
*
*
* struct MAX31855 {
* volatile int16_t thermocouple_temp; // Right-justified for 14-bit result (D31..D18)
* volatile uint8_t therm_fault; //Just D16 (so 1 bit)
* volatile int16_t internal_temp; // Right-justified for 12-bit result (D15...D4)
* volatile uint8_t therm_fault_details; // 3 bits : D2...D0 (SCVcc, SCGnd, OC)
* volatile int8_t sign; // Indicate if thermocouple temperature is positive or negative
* };
*
* struct MAX31855 MAX31855Sensor;
*
*/

void MAX31855ReadTemperature(void)
{

uint32_t readresults[4];
uint8_t count;


MAP_WatchdogReloadSet(WATCHDOG0_BASE, DEFAULT_WATCHDOG0_MULTIPLIER*getSystemClock);

// Enable CS
MAP_GPIOPinWrite(GPIO_PORTQ_BASE, GPIO_PIN_1, 0);
count = 4;
while(count != 0)
{
count--;
// Transmitting dummy byte to MAX31855
MAP_SSIDataPut(SSI3_BASE, 0x00);
// Wait for the data to be transmitted out of the SSI3 by checking on
// the busy status from the SSI controller
while(MAP_SSIBusy(SSI3_BASE));
// Receive data
MAP_SSIDataGet(SSI3_BASE, &readresults[count]);

}

// Disable CS
MAP_GPIOPinWrite(GPIO_PORTQ_BASE, GPIO_PIN_1, GPIO_PIN_1);

//Signed 14-bit temperature is from D31-D18 of overall 32-bit result
// Read 16-bit values from D31-D16 in readresults[3] and readresults[2] and adjust

MAX31855Sensor.thermocouple_temp = (int)((((readresults[3]) << 8) | ((readresults[2]) & 0xFC))>> 2); // Retrieve 2's complement 14 MSbits (which includes 2 fractional bits)
MAX31855Sensor.therm_fault = (readresults[2]) & 0x01; // D16
MAX31855Sensor.internal_temp = (int)((((readresults[1]) << 8) | ((readresults[0]) & 0xF0))>> 4);
MAX31855Sensor.therm_fault_details = (readresults[0]) & 0x07;

if(MAX31855Sensor.thermocouple_temp >= 0 )
{
MAX31855Sensor.sign = '+';
}
else
{
MAX31855Sensor.thermocouple_temp = ~MAX31855Sensor.thermocouple_temp + 1; // Take 2's complement
MAX31855Sensor.sign = '-';
}


}