MSP430AFE2XX应用笔记

最近在工作中接触到TI的MSP430AFE2XX系列产品，搭建了一套测试用调试板，其实也非常简单，就是MSP430AFE2XX + LaunchPad + LCD,见下图当然，MSP430AFE2XX芯片外围连接非常简单，VREF到AVSS之间接104电容，AVCC到AVSS之间加104电容，DVCC通过10R电阻到AVCC，RST 到DVCC 47K电阻，A0+,A0-输入端RC网络滤波；在调试过程中，人为接了一个桥模拟输入，在桥的一侧采用一个可变电阻+固定电阻，模拟信号量的改变，在测试中发现，采用USB端口供电是，ADC转换后的值后12位跳动比较厉害，后来将电源做了下调整，改用下图板上的电源，电路图如下,将其正输出电源调整到6V左右，然后再接LDO输出3.3V供给AFE2XX芯片的DVCC，通过这个连接之后，发现ADC稳定了一些，以上ADC未做软件上的滤波处理，

我们期望的目的是24的ADC转换结果跳动的位数越少越好，各位看到的朋友请多多指点。

 

以下是测试用代码，

 

#include "io430.h"
#include "S6B0741.h"
//#include  "msp430g2553.h"

#define LED_1   (0x01)                      // P1.0 LED output
#define LED_2   (0x40)                      // P1.6 LED output
#define  RED_LED_ON()               P1OUT |= (1<<0)   //P1.0  led
#define  RED_LED_OFF()              P1OUT &= (~(1<<0))
#define  RED_LED_COM()              P1OUT ^= (1<<0)

#define  Num_of_Results  10
#define FOSC  12000000

unsigned char HEX_ASCII[16]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
volatile unsigned char rec_data,rec_flag;
volatile unsigned char sec=0,min=0,hour=0;

unsigned int results,rest;
unsigned long sd24_result;

// Timer A0 interrupt service routine
#pragma vector=TIMER0_A0_VECTOR   //TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
  static unsigned char cnt=0;
 
  if((++cnt)>=100)
  {
    cnt = 0;
  if((++sec)>=60)
  {
    sec = 0;
    if((++min)>=60)
    {
       min = 0;
       if((++hour)>=24)
          hour = 0;
    }
  }
  }
}

/*************************************************************
 系统时钟 初始化函数
************************************************************/
void SysCLK_init(void)
{
  if (CALBC1_12MHZ==0xFF)           // If calibration constant erased
  {           
    while(1);                               // do not load, trap CPU!! 
  } 
  DCOCTL = 0;                               // Select lowest DCOx and MODx settings
  BCSCTL1 = CALBC1_12MHZ;                    // Set DCO
  DCOCTL = CALDCO_12MHZ;
  //BCSCTL1 &= 0xCF;
 // BCSCTL3 |=  XCAP_3;   //设置ACLK时钟源为32.768KHZ   
}

/*************************************************************
 TimerA初始化函数
************************************************************/
void TimeA_init(void)
{   
 CCTL0 |= CCIE;                             // CCR0 interrupt enabled
 CCR0 = FOSC/8/100;                         //定时长为1S
 TACTL |= TASSEL_2 + MC_1 + ID_3 ;                //时钟 ACLK，Up to CCR0, SMCLK/8
}

/*************************************************************
 UART 初始化函数
 9600@12M 8N1
************************************************************/
/*
void Uart_init(void)
{
  P1SEL = BIT1 + BIT2 ;                     // P1.1 = RXD, P1.2=TXD
  P1SEL2 = BIT1 + BIT2;                     
  UCA0CTL1 |= UCSSEL_2;                     // SMCLK
  UCA0BR0 = 226;                            // 12MHz for 9600
  UCA0BR1 = 4;                              // 12MHz for 9600
  UCA0MCTL = UCBRS0;                        // Modulation UCBRSx = 1
  UCA0CTL1 &= ~UCSWRST;                     // **Initialize USCI state machine**
  IE2 |= UCA0RXIE;                          // Enable USCI_A0 RX interrupt
}
*/
/*************************************************************
 io端口 初始化函数
************************************************************/
void GPIO_init(void)
{
  P1DIR |= LED_1 + LED_2;                    // P1.0 & P1.6 = LEDs 
  P1OUT = 0x00;
  P2DIR |= ((1<<0));   //P20,P21,P22,P23用于驱动LCD
  P1DIR |= ((1<<1)|(1<<3)|(1<<4)); //驱动LCD
}

/*************************************************************
 SD24  初始化函数
************************************************************/
void SD24_init(void)
{
   SD24CTL = SD24REFON + SD24SSEL0 + SD24XDIV_2; // + SD24DIV_2;          // 1.2V ref, SMCLK
   SD24INCTL0 =  SD24INTDLY_1;                    // Interrupt on 3rd sample
   //SD24CCTL0 |=  SD24IE ;                     // SD24LSBTOG +    Enable interrupt
   //for (i = 0; i < 0x3600; i++);             // Delay for 1.2V ref startup 
   //SD24CCTL0 |= SD24SC;                      // Set bit to start conversion
}

#pragma vector=SD24_VECTOR
__interrupt void SD24AISR(void)
{
  static unsigned int index = 0;

  switch (SD24IV)
  {
    case 2:                                   // SD24MEM Overflow
      break;
    case 4:                                   // SD24MEM0 IFG
       results = SD24MEM0;             //高16位
       SD24CCTL0 |= SD24LSBACC;            //set bit SD24LSBACC to 1;
       rest = SD24MEM0;
       SD24CCTL0 &= ~SD24LSBACC;     
      break;
    case 6:                                   // SD24MEM1 IFG
      break;
    case 8:                                   // SD24MEM2 IFG
      //results = SD24MEM0;              // Save CH2 results (clears IFG)
     // if (++index == Num_of_Results)
     // {
     //   index = 0;                            // SET BREAKPOINT HERE
     // }
      break;
  }
}

unsigned long Get_SD24(unsigned int ch)
{
   unsigned long long_temp;
   SD24INCTL0 =  SD24INTDLY_1 + ch;
   SD24CCTL0 |= SD24SC;
   while ((SD24CCTL0 & SD24IFG)==0);
   SD24CCTL0 &= ~SD24SC;
   results = SD24MEM0;             //高16位
   SD24CCTL0 |= SD24LSBACC;            //set bit SD24LSBACC to 1;
   rest = SD24MEM0;
   SD24CCTL0 &= ~SD24LSBACC;
  
   long_temp = (unsigned long)results;
   long_temp <<= 8;
   long_temp |= (unsigned long)rest;  
   return long_temp;
}
/***********************************************************
 主函数
************************************************************/
int main( void )
{
  unsigned char row;
  float float_sd24;
  
  // Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
 
  SysCLK_init(); //系统时钟初始化函数 
  TimeA_init();  //TimerA初始化
  //Uart_init();   //UART 初始化
  GPIO_init();  //IO端口初始化
  SD24_init();
 
  __bis_SR_register(GIE);       // Enter LPM0, interrupts enabled
  
   lcd_init();
   lcd_clr_all();
   lcd_put_8x16_str_xy(0,0,"For AFE221 Test");
   lcd_put_6x8_str_xy(0,14,"===================================");  
   lcd_put_6x8_str_xy(0,15,"Write By : AlexDeng");
 
   row = 3;
   lcd_put_6x8_str_xy(0,row,"TimeA UP to CCR0");
  
    
   while(1)
   {    
       //LCD显示 hour:Min:Sec     
       row = 4;
       lcd_put_8x16_char_xy(0,row,HEX_ASCII[hour/10]);
       lcd_put_8x16_char_xy(8,row,HEX_ASCII[hour%10]);
       lcd_put_8x16_char_xy(16,row,':');
       lcd_put_8x16_char_xy(24,row,HEX_ASCII[min/10]);
       lcd_put_8x16_char_xy(32,row,HEX_ASCII[min%10]);
       lcd_put_8x16_char_xy(40,row,':');
       lcd_put_8x16_char_xy(48,row,HEX_ASCII[sec/10]);
       lcd_put_8x16_char_xy(56,row,HEX_ASCII[sec%10]);
      
       /*
       row = 7;
       lcd_put_8x16_char_xy(0,row,HEX_ASCII[(results>>12)&0x0f]);
       lcd_put_8x16_char_xy(8,row,HEX_ASCII[(results>>8)&0x0f]);
       lcd_put_8x16_char_xy(16,row,HEX_ASCII[(results>>4)&0x0f]);
       lcd_put_8x16_char_xy(24,row,HEX_ASCII[results&0x0f]);
      
       row = 7;
       lcd_put_8x16_char_xy(40+0,row,HEX_ASCII[(rest>>12)&0x0f]);
       lcd_put_8x16_char_xy(40+8,row,HEX_ASCII[(rest>>8)&0x0f]);
       lcd_put_8x16_char_xy(40+16,row,HEX_ASCII[(rest>>4)&0x0f]);
       lcd_put_8x16_char_xy(40+24,row,HEX_ASCII[rest&0x0f]);
       */     
       sd24_result = Get_SD24(SD24INCH_0);      
       row = 7;
       lcd_put_8x16_char_xy(0,row,HEX_ASCII[(sd24_result>>20)&0x0f]);
       lcd_put_8x16_char_xy(8,row,HEX_ASCII[(sd24_result>>16)&0x0f]);
       lcd_put_8x16_char_xy(16,row,HEX_ASCII[(sd24_result>>12)&0x0f]);
       lcd_put_8x16_char_xy(24,row,HEX_ASCII[(sd24_result>>8)&0x0f]);
       lcd_put_8x16_char_xy(32,row,HEX_ASCII[(sd24_result>>4)&0x0f]);
       lcd_put_8x16_char_xy(40,row,HEX_ASCII[sd24_result&0x0f]);
      
       sd24_result = Get_SD24(SD24INCH_5);
       sd24_result >>= 8;
       sd24_result -= 0x8000;
       //float_sd24 = sd24_result;
       //float_sd24 *= 0.01831;
       //float_sd24 *= 1200;
       //sd24_result = (unsigned long)float_sd24;
       //sd24_result *= 11;
       //sd24_result *= 1200;
       //sd24_result /= 0xffffff;      
       row = 9;
      
       lcd_put_8x16_char_xy(0,row,HEX_ASCII[(sd24_result/10000%10)]);
       lcd_put_8x16_char_xy(8,row,HEX_ASCII[(sd24_result/1000%10)]);
       lcd_put_8x16_char_xy(16,row,HEX_ASCII[(sd24_result/100%10)]);
       lcd_put_8x16_char_xy(24,row,HEX_ASCII[(sd24_result/10%10)]);
       lcd_put_8x16_char_xy(32,row,HEX_ASCII[(sd24_result%10)]);
       //lcd_put_8x16_char_xy(32,row,HEX_ASCII[(sd24_result/1000%10)]);
       //lcd_put_8x16_char_xy(40,row,HEX_ASCII[(sd24_result/1000%10)]);
       /*
       lcd_put_8x16_char_xy(0,row,HEX_ASCII[(sd24_result>>20)&0x0f]);
       lcd_put_8x16_char_xy(8,row,HEX_ASCII[(sd24_result>>16)&0x0f]);
       lcd_put_8x16_char_xy(16,row,HEX_ASCII[(sd24_result>>12)&0x0f]);
       lcd_put_8x16_char_xy(24,row,HEX_ASCII[(sd24_result>>8)&0x0f]);
       lcd_put_8x16_char_xy(32,row,HEX_ASCII[(sd24_result>>4)&0x0f]);
       lcd_put_8x16_char_xy(40,row,HEX_ASCII[sd24_result&0x0f]);
      */
   } 
}