Hello
I am new here , my english is very bad , but somehow maybe i will make me understood .
So my problem is to decode a rotary encoder and set two outputs : one for cCW and the other to CCW .
I use an pic16f628 , and RA0, RA1 is for inputs encoder with two resistors 10k up to +5v .
RB0 , RB1 i am used for output CW and CCW . I dont need precision so if apeear some slipage , ..it s ok .

 

I use a TOKY encoder with 300 pulses/rotation . The algorithm must decode inpust from encoder and if encoder not move , the outputs must stay clear .

CODE :



list p=16f628A

#include <p16F628A.inc>

errorlevel -302

__CONFIG _CP_OFF & _LVP_OFF & _BOREN_OFF & _MCLRE_OFF & _WDT_OFF & _PWRTE_ON & _INTOSC_OSC_NOCLKOUT








ORG 0x000
goto setup


setup ; init PIC16F628A

banksel CMCON
movlw 0x07 ; turn offcomparatoRS
movwf CMCON
bsf STATUS,RP0
movlw b'00000011' ; RA0, RA1 input
movwf TRISA
clrf TRISB
bcf STATUS,RP0 ; bank 0
clrf PORTA
clrf PORTB

encoder
clrf PORTB ; this make me STOP (no movements encoder)
btfss PORTA,RA0 ; poll if it some movement RA0
goto $+2
goto encoder
btfss PORTA,RA1 ; if it is movement to RA1 then must decode
goto orar
goto antiorar


orar
movlw b'00000001' ; set to CW
movwf PORTB
btfss PORTA,RA0 ; if it is still some movement
goto $+2 ; if YES poll RA1
goto encoder ; if NOT then goto STOP
btfss PORTA,RA1 ; i detect some movement so must poll to see it is the same direction
goto orar ; it is the same so keep going the same
goto encoder ;another direction detect so jump
antiorar

movlw b'00000010' ; set CCW movement
movwf PORTB
btfss PORTA,RA0 ; if it still movement
goto $+2 ; if YES poll RA1
goto encoder ; if NOT go to STOP
btfss PORTA,RA1 ; poll RA1 to see direction
goto encoder
goto antiorar


end


P.S. I make presumtion if RA0 change state , encoder have movment , if not encoder have no movment and PORTB must cleared

 

sory about formatting the text , but the follows labels are: setup , encoder , orar , antiorar .
orar = CW , antiorar = CCW in my language

 

The CCP module would be an optimal way of capturing this if either every rising edge or the rising/falling edge of RA0 is captured and used with TMR1, the direction would be simply the state of RA1 when the rising edge occurs.
Max.

 

See:

http://forum.allaboutcircuits.com/t...quadrature-rotary-encoders.64318/#post-440211