How to use hc-05 with pic32

Question

I want to use Hc-05 bluetooth module with my pic32 controller for communicating with other bluetooth devices. I want to test the hc-05 module with my pic32 controller. I have made the hardware connections but I don't know about the code I have written a simple code to test the module.

But it is not working. The module is not responding to my AT commands. I don't know whether my code is correct or wrong. I will post my code here. Can anyone please help me?

#include <plib.h>
#include <p32xxxx.h>
/* Standard includes. */
#include <stdio.h>

#include "../hdr/Hardware_config.h"
#include "../hdr/commands.h"

#define BLT_BUF_SIZE  512

int BLT();
int i,j;
int ptr = 0;

byte BLT_BUF[BLT_BUF_SIZE];
int BLT_ptr;
char rchar;

void Serial_init()
{
  UARTConfigure(UART2, UART_ENABLE_PINS_TX_RX_ONLY);
  UARTSetLineControl(UART2, UART_DATA_SIZE_8_BITS | UART_PARITY_NONE | UART_STOP_BITS_1);
  UARTSetDataRate(UART2, GetPeripheralClock(), 9600);//57600);//);//57600);
  UARTEnable(UART2, UART_ENABLE_FLAGS(UART_PERIPHERAL | UART_RX | UART_TX));

  SetPriorityIntU2(UART_INT_PR1);
  EnableIntU2RX;

  INTEnableSystemMultiVectoredInt();
}

void __ISR(_UART_2_VECTOR, ipl2) IntUart2Handler(void)
{
  IFS1bits.U2RXIF = 0;
  while( DataRdyUART2())
  {
    BLT_BUF[ptr++] =  ReadUART2();
  }

  // We don't care about TX interrupt
  if ( INTGetFlag(INT_SOURCE_UART_TX(UART2)) )
  {
    INTClearFlag(INT_SOURCE_UART_TX(UART2));
  }
}

void main()
{
  SYSTEMConfig(GetSystemClock(), SYS_CFG_WAIT_STATES | SYS_CFG_PCACHE);
  SYSTEMConfigPerformance(GetSystemClock());
  DDPCONbits.JTAGEN=0;

  Serial_init();

  while(1)
  {
    BLT();
  }

}

int BLT()
{
  RESET:

  memset(BLT_BUF,0,sizeof(BLT_BUF));  //BLT_ptr=0;
  putsUART2("AT\r\n");
  for(i=0;i<1000;i++)
    for(j=0;j<2000;j++);

  if(!strstr(BLT_BUF,"OK"))
  {
    dly_sec(2);
    goto RESET;
  }
  memset(BLT_BUF,0,sizeof(BLT_BUF));BLT_ptr=0;
  putsUART2("AT+ROLE=1\r\n");
  for(i=0;i<1000;i++)
    for(j=0;j<2000;j++);
  if(!strstr(BLT_BUF,"OK"));
}

Thanks & Regards M.Sivakumar

Answer 1

BLT_BUF should be declared volatile for a start. Secondly, your delay should be before where you check for "OK". You have those for loops that do no meaningful delay (in all likeliness they will be optimised out by the compiler), then you expect the result to be there straight away when in all likeliness it might not be.

It is always helpful to be able to print out the contents of a buffer (BLT_BUF) so get some sort of usb converter for your pc or examine the contents via a debugger. You want to know if it receives anything at all, first and foremost. Check this before you loop back and erase the buffer.