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Port Expander Problem

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I have written a code for MCP27X17 I2C Port Expander but it is not working. Can anyone help me fix the code. I have attached the mikroC Project files and Proteus File.

Address of MCP27017 is 0x000 (A0-A2 grounded)

mikroC PRO PIC v6.0.1 C Code


Code C - [expand]
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//Project: Port Expander
//MCU:     PIC16F877A
//Clock:   8 MHz
//Author:  Jayanth Devarayanadurga
 
#define I2CMODE 1
#define SPIMODE 0
#define WrtCmd  0
#define RdCmd   1
 
//#defines are with IOCON.BANK = 0
 
#define IODIRA      0x00
#define IODIRB      0x01
#define IPOLA       0x02
#define IPOLB       0x03
#define GPINTENA    0x04
#define GPINTENB    0x05
#define DEFVALA     0x06
#define DEFVALB     0x07
#define INTCONA     0x08
#define INTCONB     0x09
#define IOCONA      0x0A
#define IOCONB      0x0B
#define GPPUA       0x0C
#define GPPUB       0x0D
#define INTFA       0x0E
#define INTFB       0x0F
#define INTCAPA     0x010
#define INTCAPB     0x011
#define GPIOA       0x012
#define GPIOB       0x013
#define OLATA       0x014
#define OLATB       0x015
 
#define IORESET PORTC.F4
#define HRDADD 0x00;
 
#define HRDWADD 6 // device hard address
unsigned char gAddrPins = HRDWADD <<1;
unsigned char SerialMode = I2CMODE;
unsigned char gControlByte = 0x40;
unsigned char mode = 0; //1 for SPI, 0 for I2C
 
void I2CWriteByte(unsigned char reg, unsigned char data_);
void Write23X17(unsigned char reg, unsigned char data_);
void ResetMCP23X17();
void InitMCP(void);
 
void ResetMCP23X17(){
 IORESET = 0;
 delay_us(100);
 //IORESET = 1;;
}
 
void SPIWriteByte(unsigned char reg, unsigned char data_)
{
   SPI1_Write(gControlByte | WrtCmd | gAddrPins);
   SPI1_Write(reg);
   SPI1_Write(data_);
 
}
 
//****************************************
//   I2CWriteByte(unsigned char addr, unsigned char byte)
//   Writes a byte to the 23017
//****************************************
/*************************************************************
   Function Name:  Write23X17
   Return Value:   void
   Parameters:     Register address, Data
   Description:    Writes a 23X17 register. I2C or SPI is in
                   global byte
**************************************************************/
void Write23X17(unsigned char reg, unsigned char data_)
{
   if(SerialMode == I2CMODE)    //If 23017 selected
      I2CWriteByte(reg, data_); //
   else                                 //Else 23S17 is selected
      SPIWriteByte(reg, data_);  //
 
}
 
void InitMCP()
{
 
 
  //Configure 23017
  //Write23X17(GPPUA,  0x00);   // Pullups
  Write23X17(IOCONA, 0x40);     //
  Write23X17(IOCONB, 0x40);
  Write23X17(IODIRA, 0x00);     //All outs
  Write23X17(IODIRB, 0x00);     //All outs
 
}
 
void I2CWriteByte(unsigned char reg, unsigned char data_)
{
   I2C1_Start();
   I2C1_Wr(gControlByte | WrtCmd | gAddrPins);
   I2C1_Wr(reg);
   I2C1_Wr(data_);
   I2C1_Stop();
}
 
void main(){
 
      TRISA = TRISB = TRISD = PORTA = PORTB = PORTD = 0x00;
      TRISC = 0x00;
      PORTC = 0x00;
      
      if(mode == 0)
      I2C1_Init(100000);
      else if(mode == 1)
      SPI1_Init();
      
      InitMCP();
 
      while(1){
      
      
          Write23X17(GPIOA, 0xAA);
      
      
      }
}





Edit: The problem is solved. It is working now.
 

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Last edited:

spudboy488

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You're not taking the part out of reset. Look in function ResetMCP23X17. IORESET=1 is commented out.
 

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