main.c

MSP430驱动数字电位器MAX5484的代码(调试已经通过).rar

#include "msp430x13x.h"

#define SCLK_HIGH P4OUT |= 0x02
#define SDA_HIGH P4OUT |= 0x04

#define SCLK_LOW P4OUT &= ~0x02
#define SDA_LOW P4OUT &= ~0x04

#define CS_HIGH P4OUT |= 0x20
#define CS_LOW P4OUT &= ~0x20
void usDelay(int microeconds)
{
    do
    {
        _NOP(); 
        _NOP();
    }while (--microeconds > 0);
}

static void InitOsc(void)
{
  WDTCTL = WDTPW + WDTHOLD;                      // stop watchdog timer

  DCOCTL = DCO0 + DCO1 + DCO2;                                  	/*  */
  BCSCTL1 =  RSEL2 + RSEL1 + RSEL0;
	BCSCTL2 = SELM1+SELS;			//	 Aclk = 1/1 XT1 urn on XT1 oscillator
//  FCTL2 = FWKEY + FSSEL0 + FN1;                  /* select MCLK/3 for flash timing */
  __bic_SR_register(OSCOFF);                     // turn on XT1 oscillator
  do
  {
    IFG1 &= ~OFIFG;                              // Clear OFIFG
    usDelay(130);                            		// Wait ~130us
  } while (IFG1 & OFIFG);                        // Test oscillator fault flag
}  

static void InitPort(void)
{
	P1DIR = 0x3f;
	P2DIR = 0x3f;
        P3DIR = 0;
	P4DIR = 0x3f;
	P5DIR = 0x3f;
	P6DIR = 0;
        P1OUT = 0;
	P2OUT = 0;
	P4OUT = 0x32;
	P5OUT = 0x00;        
}

void spi_write(long int data)
{
  int i;
  CS_LOW;
 /* for(i=0;i<8;i++)
  {
    SDA_LOW;
    SCLK_LOW;
    usDelay(20);
    SCLK_HIGH;
  }
  SCLK_LOW;*/
  data <<= 6;
  for(i=24;i>0;i--)
  {
    SCLK_LOW;
    if(data & 0x800000)
      SDA_HIGH;
    else
      SDA_LOW;
    data <<= 1;
    SCLK_HIGH;
    usDelay(1);  
  }
  SCLK_LOW;
  usDelay(1);
  CS_HIGH;  
}

void rsave(void)
{
  int i,j;
  SCLK_LOW;
  CS_LOW;
  j = 0x20;
  for(i=8;i>0;i--)
  {
    if(j & 0x80)
      SDA_HIGH;
    else
      SDA_LOW;
    j <<= 1;
    SCLK_LOW;
    SCLK_HIGH;
  }
  SCLK_LOW;
  usDelay(1);
  CS_HIGH;
  usDelay(12000);
}

void r_read(void)
{
  int i,j;
  SCLK_LOW;
  CS_LOW;
  j = 0x30;
  for(i=8;i>0;i--)
  {
    if(j & 0x80)
      SDA_HIGH;
    else
      SDA_LOW;
    j <<= 1;
    SCLK_LOW;
    SCLK_HIGH;
  }
  SCLK_LOW;
  CS_HIGH;
  usDelay(12000);
}

int main( void )
{
   WDTCTL = WDTPW + WDTHOLD;// Stop watchdog timer to prevent time out reset
  InitOsc();
  InitPort();
  spi_write(800);
  rsave();
  //r_read();  
  while(1);
}