fet140_dma_07.c

msp430f14x 系列片内外设的实例代码

//******************************************************************************
//  MSP-FET430P140 Demo - DMA0/1 Repeated Block to DAC0/1 Sin/Cos, TACCR1, XT2
//
//  Description; DMA0 and DMA1 are used to transfer a sine and cos look-up table 
//  word-by-word as a repeating block to DAC12_0 and DAC12_1. The effect is sine 
//  and cos wave outputs. Timer_A operates in upmode with TACCR1 loading 
//  DAC12_0 amd DAC12_1 on rising edge and DAC12_OIFG triggering next DMA0 
//  DMA1 transfers. DAC12_0 and DAC12_1 are grouped for gitter-free operation.
//  ACLK= n/a, MCLK= SMCLK= TACLK= XT2= 8MHz
//  //*An external 8MHz XTAL on X2IN X2OUT is required for XT2CLK*//	  
//  //* MSP430F169 Device Required*//
//
//               MSP430F169             
//            -----------------
//        /|\|            XT2IN|-  
//         | |                 | 8MHz    
//         --|RST        XT2OUT|-       
//           |                 |
//           |        DAC0/P6.6|--> ~ 10kHz sine wave
//           |        DAC1/P6.7|--> ~ 10kHz cos wave
//
//
//  M.Buccini
//  Texas Instruments, Inc
//  October 2003
//  Built with IAR Embedded Workbench Version: 1.26B
//  December 2003
//  Updated for IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include  <msp430x16x.h>

//------------------------------------------------------------------------------ 
// 12-bit Sine Lookup table with 32 steps
//------------------------------------------------------------------------------ 
static int Sin_tab[32] = {
        2048,
        2447,
        2831,
        3185,
        3495,
        3750,
        3939,
        4056,
        4095,
        4056,
        3939,
        3750,
        3495,
        3185,
        2831,
        2447,
        2048,
        1648,
        1264,
        910,
        600,
        345,
        156,
        39,
        0,
        39,
        156,
        345,
        600,
        910,
        1264,
        1648
};

static int Cos_tab[32] = {
        1648,
        1264,
        910,
        600,
        345,
        156,
        39,
        0,
        39,
        156,
        345,
        600,
        910,
        1264,
        1648,
        2048,
        2447,
        2831,
        3185,
        3495,
        3750,
        3939,
        4056,
        4095,
        4056,
        3939,
        3750,
        3495,
        3185,
        2831,
        2447,
        2048
};

void main(void)
{
 unsigned int i;
  WDTCTL = WDTPW + WDTHOLD;             // Stop WDT
  BCSCTL1 &= ~XT2OFF;                   // XT2= HF XTAL

   do 
  {
  IFG1 &= ~OFIFG;                       // Clear OSCFault flag
  for (i = 0xFF; i > 0; i--);           // Time for flag to set
  }
  while ((IFG1 & OFIFG));               // OSCFault flag still set?                

  BCSCTL2 |= SELM_2 + SELS;             // MCLK= SMCLK= XT2 (safe)
  ADC12CTL0 = REF2_5V + REFON;          // Internal 2.5V ref 

  DMACTL0 = DMA0TSEL_5 + DMA1TSEL_5;    // DAC12IFG trigger
  DMA0SA = (int) Sin_tab;               // Source block address
  DMA0DA = DAC12_0DAT_;                 // Destination single address
  DMA0SZ = 0x20;                        // Block size
  DMA0CTL = DMADT_4 + DMASRCINCR_3 + DMAEN;     // Rpt, inc src, word-word

  DMA1SA = (int) Cos_tab;               // Source block address
  DMA1DA = DAC12_1DAT_;                 // Destination single address
  DMA1SZ = 0x20;                        // Block size
  DMA1CTL = DMADT_4 + DMASRCINCR_3 + DMAEN;     // Rpt, inc src, word-word

  DAC12_0CTL = DAC12LSEL_2 + DAC12IR + DAC12AMP_5 + DAC12IFG + DAC12ENC + DAC12GRP; 
  DAC12_1CTL = DAC12LSEL_2 + DAC12IR + DAC12AMP_5 + DAC12IFG + DAC12ENC; 

  CCTL1 = OUTMOD_3;                     // CCR1 set/reset
  CCR1 = 1;                             // CCR1 PWM Duty Cycle	  
  CCR0 = 25-1;                          // Clock period of CCR0 
  TACTL = TASSEL_2 + MC_1;              // SMCLK, upmode

  _BIS_SR(CPUOFF);                      // CPU off
}