[SOLVED] Interfacing Shift Register to extend outputs of PIC12F675

[Mithun_K_Das]

As PIC12F675 doesn't have more pins to I want to add a shift register to extend its outputs. I want to use 4094 8-bit shift register. I tried some programs but can't work. Can anyone help me in this case?

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I did this program from this link with some modification. Its working good. But one problem is the Q0(PIN4) is always high.

Can you tell me where I did wrong?
Here is the Simulation image:


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/********************************************************************************
Program for Shift register using to extend MCU's I/O
Program writteb by MKDas; Date: 26-Feb, 2013.
MCU: PIC12F675; X-Tal: 8M internal
********************************************************************************/
// PIN declaration
sbit Shift_E   at GP0_bit;
sbit Shift_CLK at GP1_bit;
sbit Shift_D   at GP2_bit;

sbit Shift_E_Dirrection   at TRISIO0_bit;
sbit Shift_CLK_Dirrection at TRISIO1_bit;
sbit Shift_D_Dirrection   at TRISIO2_bit;
// End of declearation

void WriteByteToShift(unsigned Byte)
{
 unsigned char BitCount =0;
 for(BitCount=0;BitCount<8;BitCount++)
 {
  Shift_D = (((Byte>>BitCount)&0x1)!=0);
  Delay_us(10);
  Shift_CLK = 1;
  Delay_us(10);
  Shift_CLK = 0;
  Delay_us(10);
 }
}
ToggleEpin()
{
 Shift_E = 1;
 Delay_us(100);
 Shift_E = 0;
 Delay_us(100);
}


void WriteDataToShift(unsigned Data)
{
 WriteByteToShift(((Data&0xFF)>>4)|0x80); // write upper bits
 ToggleEpin();
 WriteByteToShift(((Data&0xFF))|0x80); // write lower bits
 ToggleEpin();
}

int dis;
void main() 
{
 CMCON=0x07;// turn off comparator
 ANSEL=0x07;// ADC configuration
 OSCCAL = 0xFF;// internal X-Tal settings
 TRISIO=0b00001000; // I/O settings
 GPIO=0x00;
 while (1)
  {                            // Endless loop
   while(GP3_bit==1)
   {
    dis++;
    WriteDataToShift(dis);
    Delay_ms(1000);
    break;
   }
   WriteDataToShift(0);
  }// while
}// void

 

[Mithun_K_Das]

Ahh!!!!!!!!!!!! Thanks ***!!!!!!!!. I've made it!!!!

Here is the corrected code!!!

/********************************************************************************
Program for Shift register using to extend MCU's I/O
Program writteb by MKDas; Date: 26-Feb, 2013.
MCU: PIC12F675; X-Tal: 8M internal
********************************************************************************/
// PIN declaration
sbit Shift_E   at GP4_bit;
sbit Shift_CLK at GP2_bit;
sbit Shift_D   at GP5_bit;

sbit Shift_E_Dirrection   at TRISIO4_bit;
sbit Shift_CLK_Dirrection at TRISIO2_bit;
sbit Shift_D_Dirrection   at TRISIO5_bit;
// End of declearation

void WriteByteToShift(unsigned Byte)
{
 unsigned char BitCount = 0;
 for(BitCount=0;BitCount<8;BitCount++)
 {
  Shift_D = (((Byte>>BitCount)&0x01)!=0);
  Shift_CLK = 1;
  Delay_us(10);
  Shift_CLK = 0;
  Delay_us(10);
 }
}
ToggleEpin()
{
 Shift_E = 1;
 Delay_us(10);
 Shift_E = 0;
 Delay_us(10);
}


void WriteDataToShift(unsigned Data)
{
 WriteByteToShift(((Data&0xF0)>>4)|0x00); // write upper bits
 ToggleEpin();
 WriteByteToShift(((Data&0xFF))|0x00); // write lower bits
 ToggleEpin();
}

int dis;
void main() 
{
 CMCON=0x07;// turn off comparator
 ANSEL=0x07;// ADC configuration
 OSCCAL = 0xFF;// internal X-Tal settings
 TRISIO=0b00001011; // I/O settings
 GPIO=0x00;
 while (1)
  {                            // Endless loop
   while(GP3_bit==1)
   {
    dis++;
    WriteDataToShift(dis);
    Delay_ms(100);
    break;
   }
   WriteDataToShift(0b00000000);
  }// while
}// void