- Sat May 23, 2009 12:10 am
#73392
Hello all,
Here i have enclosed the code which i'm using.This is communication between gps to pc through msp430,now i want to change it means
1. i want to receive data through software uart from gps to pc through msp
2. i wan to transfer data from pc to gps using hardware uart
could any one can help me.
#include <msp430x14x.h>
#include<stdio.h>
#include "stdarg.h"
#define RXD 0x04 // RXD on P2.2
#define TXD 0x02 // TXD on P1.1
#define Bitime_5 52 // ~ 0.5 bit length + small adjustment-(104)
#define Bitime 104 // 8.6 us bit length ~ 115942 baud-(208)
#define DELTA 488 //1953
static unsigned int RXTXData;
unsigned int i=0,j,count=0,index,I=0;
unsigned char BitCnt,buffer[];
static const char string[] = { "***STOP***O\r\n" };
void TX_Byte (void);
void RX_Ready (void);
void Set_DCO (void);
void delay(int a);
void main (void)
{
volatile unsigned int i;
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer
BCSCTL1 |= DIVA_3; // ACLK = LFXT1CLK/8
Set_DCO(); // Set DCO
CCTL0 = OUT; // TXD Idle as Mark
TACTL = TASSEL_2 + MC_2; // ACLK, continuous mode
P1SEL = TXD; // P1.1/TA0 for TXD function
P1DIR = TXD; // TXD output on P1
P2SEL = RXD; // P2.2/TA0 as RXD input
P6SEL = 0x00; // Select P6 port as I/O
P6DIR = 0xFF; // Set P6 port to Output direction
P6OUT = 0x10;
while(1)
{
for (index=0;index<250;index++)
{
RX_Ready();
_BIS_SR(LPM3_bits+GIE);
buffer[index] = RXTXData;
}
for (index=0;index<225;index++)
{
RXTXData =buffer[index];
TX_Byte();
i = 10;
do (i--);
while (i != 0);
}
RXTXData=0x0D;
TX_Byte();
}
}
// 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
//printf("%s",RXTXData);
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 = CM_2 + CCIS0+ OUTMOD0 + CAP + CCIE ; // Sync, Neg Edge, Cap
}
void Set_DCO (void) // Set DCO to selected frequency
{
unsigned int Compare, Oldcapture = 0;
CCTL2 = CM_1 + CCIS_1 + CAP; // CAP, ACLK
TACTL = TASSEL_2 + MC_2 + TACLR; // SMCLK, cont-mode, clear
while (1)
{
while (!(CCIFG & CCTL2)); // Wait until capture occured
CCTL2 &= ~CCIFG; // Capture occured, clear flag
Compare = CCR2; // Get current captured SMCLK
Compare = Compare - Oldcapture; // SMCLK difference
Oldcapture = CCR2; // Save current captured SMCLK
if (DELTA == Compare) break; // If equal, leave "while(1)"
else if (DELTA < Compare)
{
DCOCTL--;
if (DCOCTL == 0xFF) // DCO is too fast, slow it down
{
if (!(BCSCTL1 == (XT2OFF + DIVA_3)))
BCSCTL1--; // Did DCO role under?, Sel lower RSEL
}
}
else
{
DCOCTL++; // DCO is too slow, speed it down
if (DCOCTL == 0x00)
{
if (!(BCSCTL1 == (XT2OFF + DIVA_3 + 0x07)))
BCSCTL1++; // Did DCO role over? Sel higher RSEL
}
}
}
CCTL2 = 0; // Stop CCR2
TACTL = 0; // Stop Timer_A
}
// 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; // Switch from capture to compare mode
CCR0 += Bitime_5;
_BIC_SR_IRQ(SCG1 + SCG0);
}
else
{
RXTXData = RXTXData >> 1;
if (CCTL0 & SCCI) // Get bit waiting in receive latch
RXTXData |= 0x80;
BitCnt --; // All bits RXed?
if ( BitCnt == 0)
{
CCTL0 &= ~ CCIE; // All bits RXed, disable interrupt
_BIC_SR_IRQ(CPUOFF); // Clear LPM0 bits from 0(SR)
}
}
}
// 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 --;
}
}
}
