[PIC] Serial Communication Interrupt Flag in PIC18f4520 and mikrocpro for PIC

[paulfjujo]

For my education as I do not use MikroC, does the "UART1_Write()" function wait for the transmit buffer to be empty or does it just blindly pass the parameter to the TXREG?"

a test on register is done before to fill it

UART1_Write:
;__Lib_UART_c67g12.c,62 ::                 
;__Lib_UART_c67g12.c,63 ::                 
L_UART1_Write3:
0x0A72        0xB2AD              BTFSC       TXSTA, 1 
0x0A74        0xD002              BRA         L_UART1_Write4
;__Lib_UART_c67g12.c,64 ::                 
0x0A76        0x0000              NOP
0x0A78        0xD7FC              BRA         L_UART1_Write3
L_UART1_Write4:
;__Lib_UART_c67g12.c,65 ::                 
0x0A7A        0xFFAEC42E          MOVFF       FARG_UART1_Write_data_, TXREG1
;__Lib_UART_c67g12.c,66 ::                 
L_end_UART1_Write:
0x0A7E        0x0012              RETURN      0

 

[betwixt]

Thanks Paul. If it didn't check the TRMT bit it would explain some of djc's problems but we can forget that as a cause now.

Brian.

 

[djc]

Hi all,
Issue seems to be solved. It is tricky to control MAX485. MAX_CONTROL pin played a crucial role. It has to be made high at particular instance only. So as brian posted, i waited for the termination character,';' in this case. Once i got it, then a flag is set. And using that flag in main, data is transferred with some delay before making MAX_CONTROL low.Here is the code.

#include <math.h>
#define MAX_CONTROL   PORTC.B5
#define Test          PORTD.B0  //Pin 19

volatile unsigned int index=0,sdat=0,sdat_1=0,read=0,write=0,garbage=0;
volatile unsigned char input_string[12],*string;
char FND_0='1',FND_1=2,i=0;

/*********************************************************/
//void interrupt(){
void Interrupts() iv 0x0008 ics ICS_AUTO{

  if((RCIF_bit==1)) {

                      Test=~Test;

          input_string[index]=RCREG; // store the reading char

          if(input_string[index]==59) 
           { 
             write=1;
           //  index=0;
           }
           index++;
           RCIF_bit=0;
         
          
          if(index==12) index=0;


      }

}


void main() {

     TRISD = 0x00;            /*//PortD as output*/
     PORTD = 0x00;            /*//Initial value*/
     TRISC = 0b10000000;
     TRISB = 0x55;             //0 as o/p, 1 as i/p
     PORTB = 0x00;
     INTCON =0b11000000 ;           /*//0xc0;0xa0*/



    /*TXSTA  = 0b00100000;
     RCSTA = 0b10010000;

     BAUDCON.BRG16 = 0;
     TXSTA.BRGH    = 0;
     //SPBRGH:SPBRG = 129;   //for 20MHz crystal
     SPBRG = 31;   //for 20MHz crystal*/


     UART1_Init(9600);
     Delay_ms(2);
     //PIR1.RCIF=0;
     sdat=RCREG;
     PIE1 = 0b00100000;  //RCIE bit enabled
     IPR1.RCIP = 1;
     //IPR1.TXIP = 1;
     RCON.IPEN = 1;
     PIE1 = 0b00100000;  //RCIE bit enabled
     INTCON.GIE=1;
     MAX_CONTROL=0;
     index=0;
     write=0;
         while(1){
                  if(write==1){
                                  MAX_CONTROL =1;
                                  for(i=0;i<index;i++){
                                  UART1_Write(input_string[i]);
                                  Delay_us(10);
                                  }
                                  Delay_ms(1);
                                  MAX_CONTROL =0;
                      write=0;
                      index=0;
                  }
         };

}

I haven't checked any error flags here.But this code is working somehow. Now i have to implement this logic in my main program. Thank all of you guys. You helped me a lot