GPS_CHECKTIAMER serial port transceiver program

MCU serial port sending and receiving program, the following is about GPS_CHECKTIAMER, local application program

 

#define UART_R_LEN 60
#define UART_T_LEN 34

uchar idata trdata[UART_T_LEN]; //Define the serial port send buffer
uchar idata gpsdata[UART_R_LEN]; //Define the GPS data serial port receiving buffer

uchar *inlast_t = trdata; //Last put into the send buffer
uchar *outlast_t = trdata; //The last out from the send buffer
uchar *inlast_r = gpsdata; //The last entry into the receive buffer
uchar *outlast_r = gpsdata; //The last one taken from the receiving buffer
bit t_empty,t_full,r_empty,r_full; //Buffer status flag
bit new_time,t_finish; //Receiving completion flag and sending completion flag

void serail(void) interrupt 4
{
    if(TI) //If the send interrupt is set
 {
     TI = 0;
  if(!t_empty) //If the send buffer data is not sent out
  {
  
      SBUF = *outlast_t; //The last character out of the send buffer is sent to SBUF
   outlast_t++; //The last character pointer address is increased by 1
   t_full = 0; //The sending area status is not full
   if(outlast_t >= (trdata + UART_T_LEN)) //If the address of the last character sent exceeds
     outlast_t = trdata; //Address to the top and back to the bottom
   if(outlast_t == inlast_t) //If the address of the last character sent is the address of the last character sent
     t_empty = 1;
  }
  else t_finish = 1;
 }

 if(RI) //If the receive interrupt is set
 {
  RI = 0;
  if(~r_full) //If the receive buffer is not full
  {
   *inlast_r = SBUF; //The last character entering the receive buffer is sent to SBUF
   inlast_r++; //The last character address entering the receive buffer increases by 1
   r_empty = 0; //Receive buffer is not empty
   if(inlast_r >= (gpsdata + UART_R_LEN)) //If the address of the last received character exceeds
     inlast_r = gpsdata; //Address to the top and back to the bottom
   if(inlast_r == outlast_r)    

//If the address of the last character received is equal to the address of the last character taken from the receiving area
     r_full = 1; //The receiving area is full
  }
 }
}

void loadmsg(uchar *msg, int num) //Put the string into the send buffer and prepare to send
{
 int i;

 for(i=0; i= (trdata+UART_T_LEN))
    inlast_t = trdata; //Address to the top and back to the bottom
  if(inlast_t == outlast_t)
    t_full = 1; //Send buffer is full
  
 }

 if(t_finish)
 {
  TI = 1;
  t_finish = 0;
 }

}


uchar getbyte_r(void) //Get a byte from the receive buffer
{
 uchar c;
 while(r_empty); //When the receive buffer is waiting for reception
 ES = 0; //Disable serial interrupt
 c = *outlast_r; //The last data taken from the receiving buffer is assigned to C
 r_full = 0; //Receiving is not full
 outlast_r++; //The last data address taken from the receiving buffer increases by 1
 if(outlast_r >= (gpsdata + UART_R_LEN)) //If the address exceeds
   outlast_r = gpsdata; //Address back to original place
 if(outlast_r == inlast_r)    

//If the address of the last character received is equal to the address of the last character taken from the receiving area
   r_empty = 1; //The receive buffer is empty
 ES = 1; //Resume serial interrupt
 return c;
}

uchar r_state = 0;
uchar r_byte = 0;
uchar gps_chksum= 0;

void r_string(void) // Receive string
{
 uint *ptr;
  
 uchar temp;
 uchar tp[7];   

//Define the time stamp receiving area. The stored time stamp data is the time stamp that has not been converted in the receiving buffer. It is used as the transfer storage of the global time stamp

 while(!r_empty && !new_time) //If the receive buffer is not empty and the receive is not completed
 {
  temp = getbyte_r(); //Each while loop takes in one byte of received data
  switch(r_state)      

//If the data sequentially taken in conforms to the header "@@Hb", r_state position 4, enter the time stamp and GPS status byte
  {
   case 0:
    if(temp == 0x40) //@
      r_state = 1;
    break;
   case 1:
    if(temp == 0x40) //@  
    {
     r_state = 2;
     gps_chksum = 0;
    }
    else r_state = 0;
       break;
   case 2:
    if(temp == 0x48) //H
    {
                    r_state = 3;
     gps_chksum = gps_chksum^temp;
    }
    else r_state = 0;
    break;
   case 3:
    if(temp == 0x62) //b
    {
                    r_state = 4;
     r_byte = 0;
     gps_chksum = gps_chksum^temp;
    }
    else r_state = 0;
    break;
   case 4:
    if(r_byte == 47)
      { if(gps_chksum == temp)   

//After completing the useful data collection, after data conversion, the standard characters are stored in the global time stamp buffer
          {
        ptr = (uint*)(tp+2);    
                    //Send the converted data to the time stamp buffer
              gps_dt[0] = (*ptr)%100; //year
                 gps_dt[1] = tp[0]; //month
                 gps_dt[2] = tp[1]; //day
                 gps_dt[3] = tp[4]; //time
                 gps_dt[4] = tp[5]; // points
                 gps_dt[5] = tp[6]; // seconds
  
        new_time = 1;  
        }
     r_state = 0; //Reset the data used for judgment to zero so that the data can be retrieved next time
      }
    else
      {
     gps_chksum = gps_chksum^temp;

     if(r_byte <7)
          tp[r_byte] = temp;
     else if(r_byte == 38)
      gps_state = temp;

        r_byte++;
      }
    break;
      default:
       break;
  }

 }
}