this is my code to do quadrature encoding but shure no state machine
I work wih mac pic so most of us will not be able to see the code is i
attach it in e mail
Greatings
Marcel
mabel@xs4all.nl
Amsterdam


 ;****************************************************************
 ; quadrature.ASM
 ;
 ;****************************************************************


;EQUATES

          PIC84    equ 0x00
          PortA    equ 0x05
          PortB    equ 0x06
          Stepx    equ 0x0C
          Rightx   equ 0x00
          Countx   equ 0x0D
          Stepy    equ 0x0E
          Righty   equ 0x01
          County   equ 0x0F
          temp     equ 0x10
          temp2    equ 0x12
          F2Posi   equ 0x01
          Flags2   equ 0x11
          Xbit     equ 0x05       ; Switch adconvertor to Xinput PortB
          Ybit     equ 0x07       ; Switch adconvertor to Yinput portB





ORG 0x05


 Table                            ; tabel to look up previous or next step
         addwf   PCL,f
         retlw   b'00000000'
         retlw   b'00000010'
         retlw   b'00000011'
         retlw   b'00000001'




 Start
         clrf    PortA           ;
         movlw   B'00000010'     ; make pin 2 input others output
         TRIS    PortA           ; move to tristate register
         clrf    PortB           ;
         movlw   B'00000000'     ; all pin's on port B output
         TRIS    PortB           ; move to tristate register
         clrf    Stepx           ; clear step X register
         clrf    Stepy           ; clear step Y register
         clrf    TMR0            ; clear timer register
         clrf    temp            ; clear temp register
         movlw   0xff
         movwf   Countx
         movwf   County
 main
         btfsc   PortA,F2Posi
         bsf     Flags2,F2Posi
         btfsc   PORTB,Xbit      ; test xbit= horizontal    |
         goto    RightLabel_Y    ; if lo goto y = vertical  |
         bcf     PORTB,Ybit      ; Switch Yinput off        |
         bsf     PORTB,Xbit      ; Switch Xinput on         |
         ;btfss   TMR0,7         ; this gives delay for 2.048 ms
         ;goto    $-1
         ;clrf   TMR0
         goto    RightLabel_X