大家帮看看413控制串口的程序

Lemon绿茶

大家帮看看413控制串口的程序 [复制链接]

这是在TI网站找到的例程：
//
// MSP430F413
// -----------------
// /|\| XIN|-
// | | | 32kHz
// --|RST XOUT|-
// | |
// | P1.0/CCI0A/TX|--------->
// | | 9600 8N1
// | P1.1/CCI0B/RX|<---------
//
// M. Buccini
// Texas Instruments Inc.
// Feb 2005
// Built with IAR Embedded Workbench Version: 3.21A
//*****************************************************************************
#include <msp430x41x.h>

#define RXD 0x02 // RXD on P1.1
#define TXD 0x01 // TXD on P1.0

// Conditions for 9600 Baud SW UART, SMCLK = 1048576

#define Bitime_5 0x47 // ~ 0.5 bit length + small adjustment
#define Bitime 0x6C // ~ 9620 baud

unsigned int RXTXData;
unsigned char BitCnt;

void TX_Byte (void);
void RX_Ready (void);

void main (void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
FLL_CTL0 |= XCAP14PF; // Configure load caps
CCTL0 = OUT; // TXD Idle as Mark
TACTL = TASSEL_2 + MC_2; // SMCLK, continuous mode
P1SEL = TXD + RXD; // P1.0/1 TA0 for TXD/RXD function
P1DIR = TXD; // TXD output on P1

// Mainloop
for (;;)
{
RX_Ready(); // UART ready to RX one Byte
_BIS_SR(CPUOFF + GIE); // Enter LPM0 Until character RXed
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 + CCIS0 + OUTMOD0 + CM1 + CAP + CCIE; // Sync, Neg Edge, Capture
}


// Timer A0 interrupt service routine
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
CCR0 += Bitime; // Add Offset to CCR0

// RX
if (CCTL0 & CCIS0) // RX on CCI0B?
{
if( CCTL0 & CAP ) // Capture mode = start bit edge
{
CCTL0 &= ~ CAP; // 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, disa××e interrupt
_BIC_SR_IRQ(CPUOFF); // Clear LPM0 bits from 0(SR)
}
//>>>>>>>>>> Decode of Received Byte Here <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
}
}
// TX
else
{
if ( BitCnt == 0)
CCTL0 &= ~ CCIE; // All bits TXed, disa××e interrupt
else
{
CCTL0 |= OUTMOD2; // TX Space
if (RXTXData & 0x01)
CCTL0 &= ~ OUTMOD2; // TX Mark
RXTXData = RXTXData >> 1;
BitCnt --;
}
}
}
但是我用的时候怎么会不好使呢？

kittyzhang010

现在程序好用了，但是我把_BIS_SR(CPUOFF + GIE); 改为_BIS_SR( GIE);时数据又接收不到了

pengjin

把_BIS_SR(CPUOFF + GIE); 改为_BIS_SR( GIE)，是何目的？

Applent

不想进行低功耗

dandantcb

就是说整个程序不想进低功耗状态

shaohengwei

从你的程序看，当不使用低功耗时，在主循环中不断调用RX_Ready()和 TX_Byte()，但TA0中断也在定期的对CCR0和CCTL0操作 ，时序乱了，当然收不到。

zhoujianfeng

谢谢

shrlyq

如果重新算时序的话，怎么算呢？