Control a Radio PLL with a PIC

[Archangel]

Joe, How fast are you spinning the encoder? How many CPR? I have been using 500 line (2000 CPR) encoder for a gate position applacation for about 6-7 years now. No bounce because they are optical. never lose any pulses, but they are going pretty slow. (30RPM) 1000 cps. I am doing this with 16F676, no interrupts just checking the A-B states in my main. It is a fast main loop but never the less. Oh and running on 4Mhz internal OSC

Hi, I am using the "El Cheapo" mechanical encoders similar to a rotory switch, just 3 terminals A com B tried both kinds gray scale and quatdradture. I think it is losing counts during the serout routine, it should not but it does, again it could be noisy encoder too, I will know better when I get those PICs next week. I have some optical encoders here, but they have a bizillion steps per rev. These switch type have 24.
Here is the code:

@ __config _HS_OSC & _WDT_ON & _PWRTE_ON & _MCLRE_OFF  & _CP_OFF & _FCMEN_OFF & _BOR_OFF

'************************ DEFINES HERE *************************************
DEFINE OSC 20               ' set to 20mhz
INCLUDE "MODEDEFS.BAS"
clear                       ' clear out variables
 DEFINE DEBUG_REG PORTC
 DEFINE DEBUG_BIT 6
 DEFINE DEBUG_BAUD 19200
 DEFINE DEBUG_MODE 0

'********************** PIC16F690 setup ************************************
ADCON0  = 0
ADCON1  = 0
ANSEL   = 0
ANSELH  = 0
CM1CON0 = 0
CM2CON0 = 0

TrisA = %00000000
TrisB = %11000000 
TrisC = %00000000

'*********************** ASSEMBLY INTERUPT VARIABLES ***********************
wsave   var     byte $20   system
wsave1  var     byte $a0   system    ' Necessary for devices with RAM in bank1
wsave2  var     byte $120  system    ' Necessary for devices with RAM in bank2
ssave   var     byte bank0 system
psave   var     byte bank0 system     

'***************************************************************************
enc_old         VAR BYTE
enc_new         VAR BYTE
enc_tmp         var byte
enc_counter     VAR BYTE
enc_counter_old VAR BYTE
enc_scaler      var BYTE
Display         Var Byte

INTCON = %10001000      ' Enable PortB Change Interupts  
IOCB   = %11000000
pause 5500            ' wait for LCD to start 

goto start            'skip over interupt handler
'*********************** ASSEMBLY INTERUPT HANDLER *************************

define  INTHAND myint
Asm
       
myint 
    



    ;====== BEGINNING OF THE ROTARY ENCODER CODE ========
    ;The Rotary Encoder is connected to PORTB  
    ;The A signal of the encoder connected to the PIN portB.7
    ;The B signal of the encoder connected to the PIN portB.6
    ;
    ;The 4 variables used are declared in the PicBasic code.
    ;
    ;    enc_new VAR BYTE
    ;    enc_old VAR BYTE
    ;   enc_tmp VAR BYTE
    ;    enc_counter VAR WORD
    ;
    ;================================================
        
       ;Read latest input from PORTB & put the value in enc_new.
         movf    PORTB,W
         movwf  _enc_new

         ;Strip off all but the 2 MSBs in enc_new.
         movlw    0xc0             ;Create bit mask (bits 7 & 6). b'11000000' ?
         andwf   _enc_new,F       ;Zero bits 5 thru 0.

        ;check to see if encoder has moved
        movf    _enc_old,W         ;move enc_old to W
        movwf   _enc_tmp           ;put W to enc_tmp
        movf    _enc_new,W         ;move enc_new to W for XOR
        xorwf   _enc_tmp,F         ;XOR enc_tmp to detect encoder movement
        btfsc   _enc_tmp,7         ;if bit is clear, encoder moved.
        goto    Continue           ;no movement exit isr

         ;Determine the direction of the Rotary encoder.  
         rlf     _enc_old,F          ;left shift it into _enc_old to align bit 6 of 
                                 ;_enc_old with bit 7 of enc_new.

         movf    _enc_new,W          ;Move the contents of enc_new to W in order to XOR.
         xorwf   _enc_old,F         ;XOR previous inputs (in _enc_old) with latest
                                 ;inputs (in W) to determine CW or CCW.
 
          btfsc   _enc_old,7          ;Test bit 7 of result (in _enc_old).  Skip next line
                                   ;if it is 0 (direction is CCW).
         goto    Up               ;Bit is 1 (direction is CW).  Go around Down
                                 ;and increment counter.

Down
         ;Decrements enc_counter because the rotary encoder moved CCW.
        ;Decrements enc_counter (16 bit value), sets Z on exit.
              
        decf    _enc_counter,F      ; Decrement low byte
        incfsz  _enc_counter,W      ; Check for underflow
        incf    _enc_counter+1,F    ; Update
        decf    _enc_counter+1,F    ; Fixup
        movf    _enc_counter,W
        iorwf   _enc_counter+1,W    ; Set Z bit

        
        ;Add here code for the CCW LED if needed.
         ;bsf     _led            ;turn on led
         
         goto    Continue          ;Branch around UP.

Up
        ;Increments enc_counter because the rotary encoder moved CW.
        ;Increments enc_counter (16 bit value), sets Z on exit.

        incfsz  _enc_counter,W      ; Add one to low byte
        decf    _enc_counter+1,F    ; No carry (negates next step)
        incf    _enc_counter+1,F    ; Add one to high byte
        movwf   _enc_counter        ; Store updated low byte back.
        iorwf   _enc_counter+1,W    ; Set Z flag

        
       ;Add here code for the CW LED if needed.
       ;bsf     _led2                ; turn on led
    
Continue         
;       Assign the latest encoder inputs (in enc_new) to _enc_old.
         movf     _enc_new,W
         movwf   _enc_old

;       Restore saved registers
        movf    psave, W
        movwf   PCLATH
        swapf   ssave, W
        movwf   STATUS
        swapf   wsave, F
        swapf   wsave, W
        bcf     INTCON, RABIF          ; Clear the Interupt Flag
        RETFIE                             ; Return from interrupt
endasm

'***************************************************************************
'************************* PROGRAM STARTS HERE *****************************
'***************************************************************************

START:              ' Main Program starts here




enc_counter     = 0    ' set default encoder value
enc_counter_old = 0
   ' DEBUG 254,2,  "ENCODER             "  ' change display
   ' DEBUG 254,192,#Display,"                 "
   ' DEBUG 254,148,"                    "  ' clear display
   ' DEBUG 254,212,"                    "    
    
MAIN:  'see if value has changed
    if  enc_counter <> enc_counter_old then enc_counter_old = enc_counter
    Display = (enc_counter/2)
    

   
                 
    DEBUG 254,2,"ENCODER             "          ' change display
    DEBUG 254,192,#Display,"                  "
    DEBUG 254,148,"                    "  ' clear display
    DEBUG 254,212,"                    "      ' display enc_counter value
    sound portC.7,[display,1]           
                
goto MAIN

Got it here, more or less: http://www.picbasic.co.uk/forum/showthread.php?t=9700

It actually works a bit better using serout instead of debug, at least as far as the display goes, but is faster using debug, in terms of how fast the loop cycles.
I really have not invested that much time into it.