Hi Friends,

I am working on RS485 communication with PIC24F series.

When i work individually for transmission and reception it works fine but
when i try to integrate both it is not working properly.

I am not able to figure out what could be the issue with the software?

Please find the code below which i have used


#include "system.h"
#include "p24FJ32GA004.h"
#include "f_uart.h"
#ifdef __PIC24FJ32GA004__
_CONFIG1( JTAGEN_OFF & GCP_OFF & GWRP_OFF &
COE_OFF&FWDTEN_OFF&ICS_PGx2&FWPSA_PR32 &WDTPS_PS32)
_CONFIG2( FCKSM_CSDCMD & OSCIOFNC_OFF &
POSCMOD_HS&FNOSC_PRI&I2C1SEL_SEC&IOL1WAY_ON)
#else
_CONFIG1( JTAGEN_OFF & GCP_OFF & GWRP_OFF & COE_OFF & FWDTEN_OFF & ICS_PGx2)

_CONFIG2( FCKSM_CSDCMD & OSCIOFNC_OFF & POSCMOD_HS & FNOSC_PRI)
#endif
UINT8 l_receive_var;
UINT8 l_receive_sts;
void __attribute__((__interrupt__, auto_psv)) _U1TXInterrupt(void)
{
 /*clear the transmission interrupt flag everytime a byte is
   transmitted outside.
 */
   IFS0bits.U1TXIF = 0;
}
void __attribute__((__interrupt__, auto_psv)) _U1RXInterrupt(void)
{

    UINT8 fl_test;

    IFS0bits.U1RXIF = 0;
    l_receive_var = U1RXREG;
    l_receive_sts = TRUE;
}

SINT16 main (void)
{

 UINT16 fl_partiy_sel_U16;
 UINT16 i;

 fl_partiy_sel_U16 = UART_UXMODE_NO_PAR_8BIT;

 AD1PCFG = 0xffff;
 for(i = 0 ; i<1000;i++);
 /*UART1 RX remappable configuration*/
 RPINR18bits.U1RXR = 0;

 /*UART1 TX remappable configuration*/
 RPOR1bits.RP3R = 3;

 /*Configuring the reception enable RE IO as output*/
 _TRISB1_DEF = 0;

 /*Configuring the Transmission enable DE IO as output*/
 _TRISB2_DEF = 0;


 /*configuring the IO as 0 to enable the reception mode*/
 _RB1 = 0;

 _RB2 = 0;



 /*baud rate - system clock is 8 MHz*/
 U1BRG = SYSCLK /32/19200 - 1;


 U1MODE = (UART_UXMODE_EN |
     UART_UXMODE_IDLE_CON |
     UART_UXMODE_DIS_WAKE |
     UART_UXMODE_DIS_LOOPBACK |
     UART_UXMODE_DIS_ABAUD |
     fl_partiy_sel_U16 |
     UART_UXMODE_1STOPBIT);

 U1STA = (
     UART_STS_INT_TX_BUF_EMPTY  |
     UART_STS_IrDA_POL_INV_ZERO |
     UART_STS_SYNC_BREAK_DISABLED |
     UART_STS_TX_ENABLE |
     UART_STS_INT_RX_CHAR|
     UART_STS_ADR_DETECT_DIS );
     //UART_STS_RX_OVERRUN_CLEAR);

 IEC0bits.U1TXIE = 1;

 IEC0bits.U1RXIE = 1;

 IFS0bits.U1TXIF = 0;


 IFS0bits.U1RXIF = 0;

 IPC3bits.U1TXIP = 2;

 IPC2bits.U1RXIP = 3;

 IFS0bits.U1TXIF = 0;
 while(1)
 {
  if(FALSE != l_receive_sts)
  {
   l_receive_sts = FALSE;

   l_receive_var = 0;

   for(i = 0 ; i<1000;i++);

   _RB1 = 1;

   _RB2 = 1;

   for(i = 0 ; i<1000;i++);

   U1TXREG = 'A';

   _UTXEN = 1;

   for(i = 0 ; i<500;i++);

   _UTXEN = 0;

   _RB1 = 0;

   _RB2 = 0;


  for(i = 0 ; i<100;i++);

  }
 }
 return 0;
Please let me know if i need to change something in my configuration.

Please send me the example code for RS485 if available which would help me
in understanding the code

Thanks and Regards

Manju Bargavi
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