msp430xg46x_uscia0_irda_02.c

TI提供的MSP430开发例程,适合初学者练习各个功能模块的使用

//******************************************************************************
//  MSP430xG461x Demo - USCI_A0 IrDA Monitor, 4MHz SMCLK
//
//  Description: This example receives bytes through the USCI module
//  configured for IrDA mode, and sends them out as ASCII strings using UART1
//  to a PC running a terminal software. The code can be used to monitor
//  and log an IrDA communication.
//
//  MCLK = SMCLK = DCO = 4MHz, ACLK = 32kHz
//  //* An external 32kHz XTAL on XIN XOUT is required for ACLK *//
//
//                                    MSP430xG461x
//                               -----------------------
//                              |                       |
//                           /|\|                    XIN|-
//                            | |                       | 32kHz
//                            --|RST                XOUT|-
//                              |                       |
//    GP2W0116YPS   /|\         |                       |
//      -------      |          |                       |
//     |    Vcc|-----+  IrDA    |                       |
//     #    LED|-----+ 9600 8N1 |                       |
//     #    TxD|<---------------|P2.4/UCA0TXD           |
//     #    RxD|--------------->|P2.5/UCA0RXD      UTXD1|--> 115,200 8N1
//     #     SD|-----+          |                       |    Terminal SW
//     |    GND|-----+          |                       |
//      -------      |           -----------------------
//                  ---
//
//  A. Dannenberg
//  Texas Instruments Inc.
//  June 2007
//  Built with IAR Embedded Workbench Version: 3.42A
//******************************************************************************
#include "msp430xG46x.h"

unsigned char RxByte;

//  Table for nibble-to-ASCII conversion
unsigned const char Nibble2ASCII[] =
{
  '0',
  '1',
  '2',
  '3',
  '4',
  '5',
  '6',
  '7',
  '8',
  '9',
  'A',
  'B',
  'C',
  'D',
  'E',
  'F'
};

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  P2SEL |= 0x30;                            // Use P2.4/P2.5 for USCI_A0
  P4SEL |= 0x03;                            // P4.0,1 = USART1 TXD/RXD
  SCFQCTL = 121;                            // Set FLL to 3.998MHz
  SCFI0 = FLLD0 + FN_2;                     // Adjust range select
  UCA0CTL1 |= UCSWRST;                      // Set USCI_A0 SW Reset
  UCA0CTL1 = UCSSEL_2 + UCSWRST;            // Use SMCLK, keep SW reset
  UCA0BR0 = 26;                             // 4Mhz/26=153.8kHz
  UCA0BR1 = 0;
  UCA0MCTL = UCBRF_1 + UCOS16;              // Set 1st stage modulator to 1
                                            // 16-times oversampling mode
  UCA0IRTCTL = UCIRTXPL2 + UCIRTXPL0 + UCIRTXCLK + UCIREN;
                                            // Pulse length = 6 half clock cyc
                                            // Enable BITCLK16, IrDA enc/dec
  UCA0IRRCTL = UCIRRXPL;                    // Light = low pulse
  UCA0CTL1 &= ~UCSWRST;                     // Resume USCI_A0 operation
  U1CTL |= SWRST;                           // Set USART1 SW Reset
  ME2 |= UTXE1 + URXE1;                     // Enable USART1 TXD/RXD
  U1CTL = CHAR + SWRST;                     // 8-bit characters, keep SW reset
  U1TCTL = SSEL1;                           // BRCLK = SMCLK
  U1BR0 = 0x22;                             // 4MHz/115,200=34.72
  U1BR1 = 0x00;                             //
  U1MCTL = 0xdd;                            // Modulation
  U1CTL &= ~SWRST;                          // Release USART1 state machine

  while (1)
  {
    __disable_interrupt();
    IE2 |= UCA0RXIE;                        // Enable RX int
    __bis_SR_register(CPUOFF + GIE);        // Enter LPM0 w/ interrupts

    while (!(IFG2 & UTXIFG1));              // Ensure TX buffer is ready
    U1TXBUF = Nibble2ASCII[(RxByte >> 4) & 0x0f];
                                            // TX upper nibble
    while (!(IFG2 & UTXIFG1));              // Ensure TX buffer is ready
    U1TXBUF = Nibble2ASCII[RxByte & 0x0f];  // TX lower nibble
    while (!(IFG2 & UTXIFG1));              // Ensure TX buffer is ready
    U1TXBUF = ' ';                          // TX space character
  }
}

#pragma vector = USCIAB0RX_VECTOR
__interrupt void USCIAB0RX_ISR(void)
{
  RxByte = UCA0RXBUF;                       // Get RXed character
  IE2 &= ~UCA0RXIE;                         // Disable RX int
  __bic_SR_register_on_exit(CPUOFF);        // Exit LPM0
}