fet140_spi1_5616.c

msp430f14x 系列片内外设的实例代码

//******************************************************************************
//  MSP-FET430P140 Demo - USART1 SPI Interface to TLV5516 DAC
//
//  Description: Demonstrate USART0 in SPI mode interface to TLV5516 DAC. 
//  USART0 is used to transmit data to DAC, software generated frame sync 
//  pulse, DAC is updated inside CCR0 ISR operating in up-mode. 
//  ACLK= MCLK= LFXT1= UCLK0= HF XTAL= 3.58MHz
//  //** SWRST** please see MSP430x1xx Users Guide for description **//
//  //** 3.58Mhz XTAL CRYSTAL REQUIRED - NOT INSTALLED ON FET **// 
//
//               MSP430F149             
//            -----------------
//        /|\|              XIN|-  
//         | |                 | 3.58MHz   TLV5616
//         --|RST          XOUT|-       -------------
//           |             P5.0|------>|FS        OUT|--> 1kHz sine wave
//           |       SIMO0/P5.1|------>|DIN          |
//           |       UCLK0/P5.3|------>|SCLK       CS|-|
//           |                 |       |             | v
//
//
//  M.Buccini
//  September 2003
//  Built with IAR Embedded Workbench Version: 1.26B
//  December 2003
//  Updated for IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include  <msp430x16x.h>

  unsigned int pointer;                    // 16-bit value to write 

//------------------------------------------------------------------------------ 
// 12-bit Sine Lookup table with 32 steps
//------------------------------------------------------------------------------ 
static unsigned 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
};

void main(void)
{
 unsigned int i;
  WDTCTL = WDTPW + WDTHOLD;             // Stop WDT
  BCSCTL1 |= XTS;                       // ACLK= LFXT1 = 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_3;                    // MCLK= LFXT1 (safe)
  P5SEL |= 0xA;                         // P5.1,3 SPI option select
  P5DIR |= 0xB;                         // P5.0,1,3 output direction
  P5OUT &= ~0x1;                        // FS reset
  ME2 |= USPIE1;                        // Enable USART1 SPI
  UCTL1 |= CHAR + SYNC + MM;            // 8-bit SPI Master **SWRST**
  UTCTL1 = CKPH + CKPL + SSEL0 + STC;   // Inv. delayed, ACLK, 3-pin
  UBR01 = 0x2;                          // ACLK/2 for baud rate
  UBR11 = 0x0;                          // ACLK/2 for baud rate
  UMCTL1 = 0x0;                         // Clear modulation
  UCTL1 &= ~SWRST;                      // Initialize USART state machine
  pointer = 0;                          // Clear pointer
  CCTL0 = CCIE;                         // CCR0 interrupt enabled
  CCR0 = 111;                           // Clock period of CCR0 
  TACTL = TASSEL_1 + MC_1;              // ACLK, Up-mode

  _BIS_SR(LPM0_bits + GIE);            	// Enter LPM0 w/ interrupt
}

// Timer A0 interrupt service routine
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
  P5OUT |= 0x1;                       	// FS set
  P5OUT &= ~0x1;                        // FS reset
  TXBUF1 = Sin_tab[pointer] >> 8;
  TXBUF1 = Sin_tab[pointer];
  pointer++;
  pointer &= 0x1F;                           
}