initgpstime.c~

GPS 授时接收源程序代码

#include <mega128.h> 
#include "getgpstime.h"

unsigned long gpsserA_BAUD=9600;
                                
#define CRYSTAL 7372800//系统时钟7.3728MHz 

//计算和定义M128的波特率设置参数 
#define gpsserA_BAUD_SETTING (unsigned int)((unsigned long)CRYSTAL/(16*(unsigned long)gpsserA_BAUD)-1) 
#define gpsserA_BAUD_H (unsigned char)(gpsserA_BAUD_SETTING>>8) 
#define gpsserA_BAUD_L (unsigned char)(gpsserA_BAUD_SETTING)


void initgpstime(void)
{           
    // Set baud rate 
    UBRR0H = gpsserA_BAUD_H;
    UBRR0L = gpsserA_BAUD_L;
     
    // Enable receiver,enable reveive interrupt
    UCSR0B |=0x90;

    // select asyn work mode,Set frame format: 8data, 1stop bit,no parity 
    UCSR0C = 0x06;
    gpsok=0   //初始化对时成功标记；
} 

void opengps(void)
{
   PORTG &=0x1D;       //通过OUT1给模块上电
   PORTC.0 =0;         //打开串口   
 }
 
 void closegps(void)
 {
   PORTG |=0X02;
 }