吃完飯回來了，現在開始我們的ADC實踐操作。
直奔主題我們，那就是ADC程式設計操作流程是怎麼樣的。
其實通過上節理論課的學習，大家心裡都應該有了模糊的感覺，一般的步驟如下：
1、使能ADC模組時鐘（ PCLKCR0.ADCENCLK =1）
2、啟動類比電路、帶隙和參考源，ADCCTL1暫存器（ADCPWDN, ADCBGPWD, ADCREFPWD位=1）
3、使能ADC模組（ADCCTL1.ADCENABLE=1）
4、ADC中斷相關設定（參考PIE）
5、模擬IO引腳複用設定（AIOMUX1）
6、SOC配置（觸發、通道、取樣視窗）
7、編寫中斷ISR（讀取ADC結果）
瞭解了操作步驟，那我們就要了解相關的暫存器，由於暫存器又比較多，我這裡就不一一講述，大家直接去看手冊就行了

void InitAdc(void)
{
    extern void DSP28x_usDelay(Uint32 Count);

    // *IMPORTANT*
    // The Device_cal function, which copies the ADC
 
 calibration values from TI reserved
    // OTP into the ADCREFSEL and ADCOFFTRIM registers, occurs automatically in the
    // Boot ROM. If the boot ROM code is bypassed during the debug process, the
    // following function MUST be called for the ADC to function according
    // to specification. The clocks to the ADC
 
 MUST be enabled before calling this
    // function.
    // See the device data manual and/or the ADC Reference
    // Manual for more information.

        EALLOW;
        SysCtrlRegs.PCLKCR0.bit.ADCENCLK = 1;
        (*Device_cal)();
        EDIS;

    // To powerup the ADC the ADCENCLK bit should be set first to enable
    // clocks, followed by powering up the bandgap, reference circuitry, and ADC core.
    // Before the first conversion is performed a 5ms delay must be observed
    // after power up to give all analog circuits time to power up and settle

    // Please note that for the delay function below to operate correctly the
    // CPU_RATE define statement in the DSP2802x_Examples.h file must
    // contain the correct CPU clock period in nanoseconds.
    EALLOW;
    AdcRegs.ADCCTL1.bit.ADCBGPWD  = 1;      // Power ADC BG
    AdcRegs.ADCCTL1.bit.ADCREFPWD = 1;      // Power reference
    AdcRegs.ADCCTL1.bit.ADCPWDN   = 1;      // Power ADC
    AdcRegs.ADCCTL1.bit.ADCENABLE = 1;      // Enable ADC
    AdcRegs.ADCCTL1.bit.ADCREFSEL = 0;      // Select interal BG
    EDIS;

    DELAY_US(ADC_usDELAY);         // Delay before converting ADC channels
}

初始化函式已經把我們的前三步都做完了，也就是使能時鐘、上電、使能ADC模組；
那我們現在來進行SOC相關設定，也就是：觸發源、取樣時隙、通道選擇。
觸發源我們選擇定時器0，因為我們做測試肯定輸入一個穩定的直流電壓，那用定時器最方便。
AdcRegs.ADCSOC0CTL.bit.TRIGSEL = 1;
取樣時隙就用最短時隙，也就是AdcRegs.ADCSOC0CTL.bit.ACQPS = 6;
由於TI那個實驗板只引出了幾個ADC引腳而已，我們就用ADCINA1，也就是AdcRegs.ADCSOC0CTL.bit.CHSEL = 1;
另外，我們說了，我們本次的實驗是順序取樣，遲中斷，那就是：
AdcRegs.ADCSAMPLEMODE.bit.SIMULEN0 = 1;
AdcRegs.ADCCTL1.bit.INTPULSEPOS = 1;
到這裡SOC相關設定就完成了，我們現在開始要對PIE中斷就行相應的設定了。
我們這裡採用簡單的中斷1，EOC脈衝觸發ADCINTx脈衝
AdcRegs.INTSEL1N2.bit.INT1SEL = 0;
AdcRegs.INTSEL1N2.bit.INT1CONT = 1;
AdcRegs.INTSEL1N2.bit.INT1E = 1;
最後還要再PIE組裡面開啟ADCINT1開關：PieCtrlRegs.PIEIER1.bit.INTx1 = 1;
ADC中斷函式就一個置位：

interrupt void ADCINT1_ISR(void)   // ADC  (Can also be ISR for INT10.1 when enabled)
{
  // Insert ISR Code here

  // To receive more interrupts from this PIE group, acknowledge this interrupt
   PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

  // Next two lines for debug only to halt the processor here
  // Remove after inserting ISR Code

  //asm ("      ESTOP0");
  //for(;;);

}

ADC中斷也說完了，還有定時器設定，這個就參考我們前面寫的那個程式，一模一樣，也就是說取樣時隙是1ms
首先是CPU.c檔案

void InitCpuTimers(void)
{
    // CPU Timer 0
    // Initialize address pointers to respective timer registers:
    CpuTimer0.RegsAddr = &CpuTimer0Regs;
    // Initialize timer period to maximum:
    CpuTimer0Regs.PRD.all  = 1000;
    // Initialize pre-scale counter to divide by 1 (SYSCLKOUT):
    CpuTimer0Regs.TPR.bit.TDDR  = 59;
    CpuTimer0Regs.TPRH.bit.TDDRH = 0;
    // Make sure timer is stopped:
    CpuTimer0Regs.TCR.bit.TSS = 1;
    // Reload all counter register with period value:
    CpuTimer0Regs.TCR.bit.TRB = 1;
    // Reset interrupt counters:
    CpuTimer0.InterruptCount = 0;

// CpuTimer 1 and CpuTimer2 are reserved for DSP BIOS & other RTOS
// Do not use these two timers if you ever plan on integrating
// DSP-BIOS or another realtime OS.
//
// Initialize address pointers to respective timer registers:
    CpuTimer1.RegsAddr = &CpuTimer1Regs;
    CpuTimer2.RegsAddr = &CpuTimer2Regs;
    // Initialize timer period to maximum:
    CpuTimer1Regs.PRD.all  = 0xFFFFFFFF;
    CpuTimer2Regs.PRD.all  = 0xFFFFFFFF;
    // Initialize pre-scale counter to divide by 1 (SYSCLKOUT):
    CpuTimer1Regs.TPR.all  = 0;
    CpuTimer1Regs.TPRH.all = 0;
    CpuTimer2Regs.TPR.all  = 0;
    CpuTimer2Regs.TPRH.all = 0;
    // Make sure timers are stopped:
    CpuTimer1Regs.TCR.bit.TSS = 1;
    CpuTimer2Regs.TCR.bit.TSS = 1;
    // Reload all counter register with period value:
    CpuTimer1Regs.TCR.bit.TRB = 1;
    CpuTimer2Regs.TCR.bit.TRB = 1;
    // Reset interrupt counters:
    CpuTimer1.InterruptCount = 0;
    CpuTimer2.InterruptCount = 0;

}

然後是定時中斷函式

interrupt void  TINT0_ISR(void)      // CPU-Timer 0
{
  // Insert ISR Code here

  // To receive more interrupts from this PIE group, acknowledge this interrupt
  PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

  // Next two lines for debug only to halt the processor here
  // Remove after inserting ISR Code
//  asm ("      ESTOP0");
//  for(;;);
}

最後是相關中斷設定

   CpuTimer0Regs.TCR.bit.TIE = 1;
   StartCpuTimer0();
   EALLOW;
   PieCtrlRegs.PIEIER1.bit.INTx7 = 1;
   PieCtrlRegs.PIECTRL.bit.ENPIE = 1;
   IER |= 0x0001;
   EINT;
   EDIS;

現在定時中斷也寫完了，就剩下ADC處理顯示函數了

   while(1)
   {
       if(AdcRegs.ADCSOCFLG1.bit.SOC0==1)
       {
           while(AdcRegs.ADCSOCFLG1.bit.SOC0==1);
           AdcRegs.ADCINTFLGCLR.bit.ADCINT1 = 1;
           DELAY_US(10);
           sum+=AdcResult.ADCRESULT0;
           i++;
       }
       if(i==100)
       {
           sum/=100;
           vol=sum*3.3/4095;
           WRITECMD_LCD12864(0x01);
           DISLPLAY_LONGSTRING(2,0,sum);
           DISLPLAY_FLOATSTRING(3,0,vol);
           WRITEDATA_LCD12864('v');
           sum=0;
           i=0;
       }
   }

我是直接寫在while死迴圈裡面的，然後去捕捉轉換標誌位，取樣100次，取平均值。
下載程式驗證，成功，呵呵，上大家上效果圖

突然想到一個剛才除錯的問題，就是提示我.text段超出空間，我把段大小相應調整了下
.text : > PRAML0, PAGE = 0
PRAML0 : origin = 0x008000, length = 0x000c00
DRAML0 : origin = 0x008c00, length = 0x000400

具體的程式碼我會傳到下載庫和QQ群裡面，大家有需要的話自行下載
菜鳥交流qq群107691092