2051gps.c

2051解码GPS数据装置的源代码,有详细的中文注释

/*************************************
    GPS解码1602显示程序
    作者：BG4UVR
最后更新：
2007.01.27
    1.2版，改时间由RMC语句解码，取消日期显示
2007.01.25
    1.1版，修正定位后页面不能转换的BUG。
    1.0版，基本功能。
***************************************/

#include <reg2051.h>
#include "1602.h"

sbit GPS_SPD=P1^1;
sbit SPD_TYPE=P1^0;
sbit KEY1=P3^7;

/*
sbit GPS_SPD=P1^4;
sbit KEY1=P1^6;
sbit SPD_TYPE=P1^5;
*/

//各位见笑了，加密存储开机版权信息。免得被人改目标代码 :D
unsigned char code info[]={    'D'^0xab,'e'^0xab,'s'^0xab,'i'^0xab,'g'^0xab,'n'^0xab,' '^0xab,'b'^0xab,
                            'y'^0xab,' '^0xab,'B'^0xab,'G'^0xab,'4'^0xab,'U'^0xab,'V'^0xab,'R'^0xab,};

char code TIME_AREA= 8;            //时区

//GPS数据存储数组
unsigned char JD[10];            //经度
unsigned char JD_a;            //经度方向
unsigned char WD[9];            //纬度
unsigned char WD_a;            //纬度方向
unsigned char time[6];        //时间
unsigned char speed[5];        //速度
unsigned char high[6];        //高度
unsigned char angle[5];        //方位角
unsigned char use_sat[2];        //使用的卫星数
unsigned char total_sat[2];    //天空中总卫星数
unsigned char lock;            //定位状态

//串口中断需要的变量
unsigned char seg_count;        //逗号计数器
unsigned char dot_count;        //小数点计数器
unsigned char byte_count;        //位数计数器
unsigned char cmd_number;        //命令类型
unsigned char mode;                //0：结束模式，1：命令模式，2：数据模式
unsigned char buf_full;            //1：整句接收完成，相应数据有效。0：缓存数据无效。
unsigned char cmd[5];            //命令类型存储数组

//显示需要的变量
unsigned int dsp_count;        //刷新次数计数器
unsigned char time_count;
bit page;
bit spd_type;

void sys_init(void);
bit chk_key(void);

main()
{
    unsigned char i;
    char Bhour;
    unsigned int Knots;
    sys_init();

    while(1){
        if(buf_full==0)                //无GPS信号时
        {
            dsp_count++;
            if(dsp_count>=65000){
                LCD_cls();            //清屏
                LCD_write_string(0,0,"No GPS connect..");
                while(buf_full==0);
                LCD_cls();    
                dsp_count=0;
            }
        }
        else{                        //有GPS信号时
            if(chk_key()){                //检测到按键切换显示
                page=!page;
                LCD_cls();
            }

            if(!page){                        //页面1
                if(buf_full|0x01){                //GGA语句
                    if(lock=='0'){                    //如果未定位
                        LCD_write_string(0,0,"*---.--.----  ");
                        LCD_write_string(0,1,"* --.--.----  ");                    
                    }else{                            //如果已定位
                        LCD_write_char(0,0,JD_a);            //显示经度
                        for(i=0;i<3;i++){
                            LCD_write_char(i+1,0,JD[i]);
                        }
                        LCD_write_char(4,0,'.');
                        for(i=3;i<10;i++){
                            LCD_write_char(i+2,0,JD[i]);
                        }

                        LCD_write_char(0,1,WD_a);            //显示纬度
                        LCD_write_char(1,1,' ');
                        for(i=0;i<2;i++){
                            LCD_write_char(i+2,1,WD[i]);
                        }            
                        LCD_write_char(4,1,'.');
                        for(i=2;i<9;i++){
                            LCD_write_char(i+3,1,WD[i]);
                        }                            }
                    LCD_write_char(14,0,use_sat[0]);        //显示接收卫星数
                    LCD_write_char(15,0,use_sat[1]);
                    buf_full&=~0x01;
                    dsp_count=0;
                }
                if(buf_full|0x02){                //GSV语句
                    LCD_write_char(14,1,total_sat[0]);
                    LCD_write_char(15,1,total_sat[1]);
                    buf_full&=~0x02;
                    dsp_count=0;
                }
                if(buf_full|0x04){
                    buf_full&=~0x04;
                    dsp_count=0;
                }
            }
            else{                            //页面2
                if(buf_full|0x01){                //GGA语句
                    buf_full&=~0x01;
                    dsp_count=0;
                }
                if(buf_full|0x02){
                    buf_full&=~0x02;
                    dsp_count=0;
                }
                if(buf_full|0x04){                //RMC语句
                    Bhour=((time[0]-0x30)*10+time[1]-0x30)+TIME_AREA;
                    if(Bhour>=24){
                        Bhour-=24;
                    }else if(Bhour<0){
                        Bhour+=24;
                    }
                    LCD_write_string(2,1,"BJT ");
                    LCD_write_char(6,1,Bhour/10+0x30);
                    LCD_write_char(7,1,Bhour%10+0x30);
                    LCD_write_char(8,1,':');
                    LCD_write_char(9,1,time[2]);
                    LCD_write_char(10,1,time[3]);
                    LCD_write_char(11,1,':');
                    LCD_write_char(12,1,time[4]);
                    LCD_write_char(13,1,time[5]);
                    if(spd_type){
                        LCD_write_string(5,0,"km/h A");
                    }else{
                        LCD_write_string(5,0,"knot A");
                    }
                    if(lock=='0'){                    //如果未定位
                        LCD_write_string(0,0,"---.-");
                        LCD_write_string(11,0,"---.-");
                    }else{                            //已经定位
                        if(spd_type){                    //km/h显示
                            for(i=0;i<5;i++){
                                LCD_write_char(i,0,speed[i]);
                            }
                        }else{                            //knot显示
                            Knots=    (((speed[0]-0x30)*1000
                                    +(speed[1]-0x30)*100
                                    +(speed[2]-0x30)*10
                                    +(speed[4]-0x30))*1000)/1852;
                            LCD_write_char(0,0,Knots/1000+0x30);
                            LCD_write_char(1,0,(Knots%1000)/100+0x30);
                            LCD_write_char(2,0,(Knots%100)/10+0x30);
                            LCD_write_char(3,0,'.');
                            LCD_write_char(4,0,Knots%10+0x30);
                        }
                        for(i=0;i<5;i++){
                            LCD_write_char(11+i,0,angle[i]);
                        }
                    }
                    buf_full&=~0x04;
                    dsp_count=0;
                }
            }
        }
    }
}

bit chk_key(void)
{
    if(!KEY1){
        delayms(10);
        if(!KEY1){
            while(!KEY1);
            delayms(10);
            return(1);
        }
    }
    return(0);
}

//系统初始化
void sys_init() {
    unsigned char i;
    SCON = 0x50;     /* SCON: mode 1, 8-bit UART, enable rcvr */
    TMOD = 0x21;     /* TMOD: timer 1, mode 2, 8-bit reload */
    if(GPS_SPD){
        TH1 = 0xfd;         /* TH1: reload value for 9600 baud @ 11.059MHz */
    }else{
        TH1 = 0xfa;            /* TH1: reload value for 4800 baud @ 11.059MHz */
    }
    if(SPD_TYPE){
        spd_type=1;            //速度单位km/h
    }else{
        spd_type=0;            //速度单位knot
    }
    TR1 = 1;         /* TR1: timer 1 run */
    LCD_init();        //初始化LCD
    LCD_write_string(0,0,"GPS Monitor V1.2");
    for(i=0;i<16;i++){                                //显示版权信息
        LCD_write_char(i,1,info[i]^0xab);
    }
    for(i=1;i<4;i++){
        delayms(250);
    }
    LCD_cls();
    IE=0x90;            //开总中断、串口中断
}

//串口接收中断
void uart(void) interrupt 4
{
    unsigned char tmp;
    if(RI){
        tmp=SBUF;
        switch(tmp){
            case '$':
                cmd_number=0;        //命令类型清空
                mode=1;                //接收命令模式
                byte_count=0;        //接收位数清空
                break;
            case ',':
                seg_count++;        //逗号计数加1
                byte_count=0;
                break;
            case '*':
                switch(cmd_number){
                    case 1:
                        buf_full|=0x01;
                        break;
                    case 2:
                        buf_full|=0x02;
                        break;
                    case 3:
                        buf_full|=0x04;
                        break;
                }
                mode=0;
                break;
            default:
                if(mode==1){
                    //命令种类判断
                    cmd[byte_count]=tmp;            //接收字符放入类型缓存
                    if(byte_count>=4){                //如果类型数据接收完毕，判断类型
                        if(cmd[0]=='G'){
                            if(cmd[1]=='P'){
                                if(cmd[2]=='G'){
                                    if(cmd[3]=='G'){
                                        if(cmd[4]=='A'){
                                            cmd_number=1;
                                            mode=2;
                                            seg_count=0;
                                            byte_count=0;
                                        }
                                    }
                                    else if(cmd[3]=='S'){
                                        if(cmd[4]=='V'){
                                            cmd_number=2;
                                            mode=2;
                                            seg_count=0;
                                            byte_count=0;
                                        }
                                    }
                                }
                                else if(cmd[2]=='R'){
                                    if(cmd[3]=='M'){
                                        if(cmd[4]=='C'){
                                            cmd_number=3;
                                            mode=2;
                                            seg_count=0;
                                            byte_count=0;
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
                else if(mode==2){
                    //接收数据处理
                    switch (cmd_number){
                        case 1:                //类型1数据接收。GPGGA
                            switch(seg_count){
                                case 2:                                //纬度处理
                                    if(byte_count<9){
                                        WD[byte_count]=tmp;
                                    }
                                    break;
                                case 3:                                //纬度方向处理
                                    if(byte_count<1){
                                        WD_a=tmp;
                                    }
                                    break;
                                case 4:                                //经度处理
                                    if(byte_count<10){
                                        JD[byte_count]=tmp;
                                    }
                                    break;
                                case 5:                                //经度方向处理
                                    if(byte_count<1){
                                        JD_a=tmp;
                                    }
                                    break;
                                case 6:                                //定位判断
                                    if(byte_count<1){
                                        lock=tmp;
                                    }
                                    break;
                                case 7:                                //定位使用的卫星数
                                    if(byte_count<2){
                                        use_sat[byte_count]=tmp;
                                    }
                                    break;
                                case 9:                                //高度处理
                                    if(byte_count<6){
                                        high[byte_count]=tmp;
                                    }
                                    break;
                            }
                            break;
                        case 2:                //类型2数据接收。GPGSV
                            switch(seg_count){
                                case 3:                                //天空中的卫星总数
                                    if(byte_count<2){
                                        total_sat[byte_count]=tmp;
                                    }
                                    break;
                            }
                            break;
                        case 3:                //类型3数据接收。GPRMC
                            switch(seg_count){
                                case 1:
                                    if(byte_count<6){                //时间处理
                                        time[byte_count]=tmp;    
                                    }
                                    break;
                                case 7:                                //速度处理
                                    if(byte_count<5){
                                        speed[byte_count]=tmp;
                                    }
                                    break;
                                case 8:                                //方位角处理
                                    if(byte_count<5){
                                        angle[byte_count]=tmp;
                                    }
                                    break;
                            }
                            break;
                    }
                }
                byte_count++;        //接收数位加1
                break;
        }
    }
    RI=0;
}