AVRFreaks.net

#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include "../TP_Includes/TP_Delay.h"

#define Encoder_Pin_1   2   // The pins the encoder is on (INT2)
#define Encoder_Pin_2   3  // Other Pin
#define Encoder_Input_Port   PINB   //The port the encoder is on
#define Encoder_Input_Port_DDR   DDRB   //the port direction register -

volatile static int Encoder; //volatile variable that's update in ISR

void Encoder_Init(void) // Initialise Encoder
{
   Encoder=0;
   Encoder_Input_Port_DDR &= ~((1<<Encoder_Pin_1) | (1<<Encoder_Pin_2));   //set the pins on the encoder port for input
   MCUCSR &= ~(1<<ISC2);    //Clear the ISC2 bit to 0 (falling edge trigger on INT2) in the MCUCSR
   GICR |= (1<<INT2);    //Enable the INT 2 interrupt
}

ISR(INT2_vect)   // Interrupt Service Routine for INT on encoder
{
   _delay_us(100);  // Debounce Delay  **Same problem with this line removed
if (!(Encoder_Input_Port & (1<<Encoder_Pin_1)))   // Check if Port bit is low still = valid turn of encoder  **Same problem with this line removed
   {
      if (Encoder_Input_Port & (1<<Encoder_Pin_2)) Encoder=1; else Encoder=-1;         // If the other pin is high rotate is one way otherwise rotate is the other way
   }
      
}

...
int a;
...
sei();
....
Encoder_Init();

there is a loop with this line in it
 a+=Encoder;

volatile static int Encoder;

volatile static signed char Encoder;

  .
  .
  .
#include <gray.h>
  .
  .
  .
/*************************************************************
 * Global Variables
 *************************************************************/
bit SwitchA, SwitchB;
bit EncoderCCW, EncoderCW;
  .
  .
  .
/*************************************************************
 * Task:        user_interface_task()
 *
 * Description:  Checks both pushbuttons and rotary encoder. Sets global bit(s) if
 *                    activity detected.
 *
 * Globals:     SwitchA
 *              SwitchB
 *              EncoderCW
 *              EncoderCCW
 *
 *************************************************************/
void user_interface_task(void)
{
     unsigned char responseTask;
     unsigned char current, save;
     unsigned char sav, enc;
     unsigned char command;
     unsigned char CWcount, CCWcount;
     unsigned char CWsave, CCWsave;

     current = save = PINF & 0x0f;
     enc = SwitchA = SwitchB = EncoderCCW = EncoderCW = 0;
     responseTask = NO_TASK;
     CWcount = CCWcount = 0;


    /*
     * Check the switches and rotary encoder for activity every 4 ticks
     */
     while (1)
     {
          PR_Wait_Semaphore(4);
          command = PR_Query_Semaphore();
          switch (command)
          {
          case UI_REG_RESP_CMD:
               responseTask = uiResponseTask;
               break;
          case WAIT_TIMEOUT:
               if ((PINF & 0x0f) != save)
                    PR_Wait_Ticks(10);
               current = PINF & 0x0f;
               if (current != save)
               {
                    /*
                     * If switch pressed, respective global bit variable = 1.
                     */
                    SwitchA = (~current >> 3) & 1;
                    SwitchB = (~current >> 2) & 1;

                    /*
                     * Set the global CW bit if rotary encoder was rotated CW.
                     * Set the global CCW bit if rotary encoder was rotated CCW.
                     * Clear global CW and CCW bits if no change in rotary
                     * encoder position.
                     */
                    enc = gray2binc(current & 3);
                    sav = gray2binc(save & 3);
                    if (((enc - sav) == 1) || ((enc == 0) && (sav == 3)))
                    {
                         EncoderCW = 1;
                         EncoderCCW = 0;
                    }
                    else if (((sav - enc) == 1) || ((sav == 0) && (enc == 3)))
                    {
                         EncoderCW = 0;
                         EncoderCCW = 1;
                    }
                    else
                    {
                         EncoderCW = 0;
                         EncoderCCW = 0;
                    }

                    save = current;

                    /*
                     * Send semaphore to the registered task.
                     */
                    if ((SwitchA || SwitchB || (EncoderCW) || (EncoderCCW)) && (responseTask != NO_TASK))
                    {
                         CWcount = CCWcount = 0;
                         PR_Send_Semaphore(responseTask, UI_EVENT);
                    }

               }
               break;
          default:
               while (1) {}
               break;
          }
     }
}

  .
  .
  .