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msp430f149,timer 急问:msp430f149的timer_a的串行通信应用

院士
2006-12-22 22:43:00    评分
msp430f149,timer 急问:msp430f149的timer_a的串行通信应用



关键词: msp430f149     timer     急问     串行     通信    

院士
2006-12-22 22:43:00    评分
2楼
问 我用ccr0做串行通信,可是一直都无法达到捕获,不知程序问题出在哪,希望大侠帮我看看,谢谢啦。基本是参照lierda给的参考应用程序编的
#define TXD 0x04 // TXD on P2.2
#define RXD 0x02 // RXD on P1.1

// Conditions for 2400 Baud SW UART, ACLK = 32768

#define Bitime_5 0x06 // ~ 0.5 bit length + small adjustment
#define Bitime 0x0E // 427us bit length ~ 2341 baud

unsigned int RXTXData;
unsigned char BitCnt;
unsigned int flag=0;
void TX_Byte (void);
void RX_Ready (void);
#include <MSP430x14x.h>

void main (void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
CCTL0 = OUT; // TXD Idle as Mark
TACTL = TASSEL0+TACLR+MC1; // ACLK, continous mode
P1SEL = RXD; // P1.1/TA0 for RXD function
P2DIR = TXD; // TXD output on P2
P2SEL = TXD; // P2.2/TA0 as TXD input

for (;;)
{
RX_Ready(); // UART ready to RX one Byte
_BIS_SR(GIE); // Enter LPM3 Until character RXed
do _NOP();
while(flag==0);
TX_Byte(); // TX Back RXed Byte Received
}
}


// Function Transmits Character from RXTXData Buffer
void TX_Byte (void)
{
BitCnt = 0xA; // Load Bit counter, 8data + ST/SP
CCR0 = TAR; // Current state of TA counter
CCR0 += Bitime; // Some time till first bit
RXTXData |= 0x100; // Add mark stop bit to RXTXData
RXTXData = RXTXData << 1; // Add space start bit
CCTL0 = OUTMOD0+CCIE; // TXD = mark = idle
while ( CCTL0 & CCIE ); // Wait for TX completion
}


// Function Readies UART to Receive Character into RXTXData Buffer
void RX_Ready (void)
{
BitCnt = 0x8; // Load Bit counter
CCTL0 = SCS+CCIS_0+OUTMOD0+CM1+CAP+CCIE;// Sync, Neg Edge,Captur
}


// Timer A0 interrupt service routine
interrupt[TIMERA0_VECTOR] void Timer_A (void)
{
CCR0 += Bitime; // Add Offset to CCR0
if (CCTL0 & CCIS_0) // RX on CCI0A?
{
if( CCTL0 & CAP ) // Capture mode = start bit edge
{
CCTL0 &= ~ CAP; // Switch from capture to compare mode
CCR0 += Bitime_5;
}
else
{
RXTXData = RXTXData >> 1;
if (CCTL0 & SCCI) // Get bit waiting in receive latch
RXTXData |= 0x80;
BitCnt --; // All bits RXed?
if ( BitCnt == 0)
//>>>>>>>>>> Decode of Received Byte Here
{
CCTL0 &= ~ CCIE; // All bits RXed, disable interrupt
//_BIC_SR(LPM3_bits); // Clear LPM3 bits from 0(SR)
flag=1;
}
//>>>>>>>>>> Decode of Received Byte Here
}
}
// TX
else
{
if ( BitCnt == 0)
CCTL0 &= ~ CCIE; // All bits TXed, disable interrupt
else
{
CCTL0 |= OUTMOD2; // TX Space
if (RXTXData & 0x01)
CCTL0 &= ~ OUTMOD2; // TX Mark
RXTXData = RXTXData >> 1;
BitCnt --;
}
}
} 1: 你没开中断,在FOR前面加_EINT();

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