DRV8301_SPI.c

//============================================================================
//============================================================================
//
// FILE:  DRV8301_SPI.c
//
// TITLE: DRV8301 SPI comm functions
//
// Version: 1.0
//
// Date:  24 May 2011
//
//============================================================================
//============================================================================
#include "PeripheralHeaderIncludes.h"
#include "DRV8301_SPI.h"

/*****************************************************************************/
// Initialize the SPI peripheral
/*****************************************************************************/
void DRV8301_SPI_Init(volatile struct SPI_REGS *s)
{
  s->SPICCR.bit.SPISWRESET = 0;     // Put SPI in reset state
  s->SPICCR.bit.SPICHAR = 0xF;    // 16-bit character
  s->SPICCR.bit.SPILBK = 0;         // loopback off
  s->SPICCR.bit.CLKPOLARITY = 0;    // Rising edge without delay

  s->SPICTL.bit.SPIINTENA = 0;    // disable SPI interrupt
  s->SPICTL.bit.TALK = 1;       // enable transmission
  s->SPICTL.bit.MASTER_SLAVE = 1;   // master
  s->SPICTL.bit.CLK_PHASE = 0;      // Rising edge without delay
  s->SPICTL.bit.OVERRUNINTENA = 0;  // disable reciever overrun interrupt

  s->SPIBRR = 0;            // SPICLK = LSPCLK / 4 (max SPICLK)

  s->SPICCR.bit.SPISWRESET=1;     // Enable SPI
}

/*****************************************************************************/
// Read from a DRV8301 Register
/*****************************************************************************/
Uint16 DRV8301_SPI_Read(volatile struct SPI_REGS *s, Uint16 address)
{
  union DRV8301_SPI_WRITE_WORD_REG w;
  volatile Uint16 dummy;

  w.bit.R_W = 1;              //we are initiating a read
  w.bit.ADDRESS = address;        //load the address
  w.bit.DATA = 0;             //dummy data;

  s->SPITXBUF = w.all;          //send out the data

  while(s->SPISTS.bit.INT_FLAG == 0);   //wait for the packet to complete

  dummy = s->SPIRXBUF;          //dummy read to clear the INT_FLAG bit

  w.bit.R_W = 1;              //we are initiating a read
  w.bit.ADDRESS = address;        //load the address
  w.bit.DATA = 0;             //dummy data;

  s->SPITXBUF = w.all;          //send out the data

  while(s->SPISTS.bit.INT_FLAG == 0);   //wait for the packet to complete

  dummy = s->SPIRXBUF;          //dummy read to clear the INT_FLAG bit

  return(dummy);

}

/*****************************************************************************/
// Write to a DRV8301 Register
// SPI writes always clock out the data in Status Register 1.
// Since it's available we'll return the status from this function
/*****************************************************************************/
Uint16 DRV8301_SPI_Write(volatile struct SPI_REGS *s, Uint16 address, Uint16 data)
{
  union DRV8301_SPI_WRITE_WORD_REG w;
  volatile Uint16 stat_reg1;

  w.bit.R_W = 0;              //we are initiating a write
  w.bit.ADDRESS = address;        //load the address
  w.bit.DATA = data;            //data to be written;

  s->SPITXBUF = w.all;          //send out the data

  while(s->SPISTS.bit.INT_FLAG == 0);   //wait for the packet to complete

  stat_reg1 = s->SPIRXBUF;        //read returned value of Status Register 1 and clear the INT_FLAG bit

  return(stat_reg1);

}