Instant Int and encoder (Elect. Gearing)

[boroko]

Hi All,
Been banging my head for a while now and I am getting closer. Thank you for the time you have taken to add life to this forum.

The Travel encoder section works pretty well, but the Manual encoder is erratic and sometimes take over the travel section and not let it work. A bump on Manual, and the Travel works again.

As a reminder. The Travel generates Pulse and Direction in one direction only. The Manual is for bi-directional fine adjustment after the Travel section's movement is complete (automatic). Target: 12F675 @ 4mHz INT_OSC

Anybody see what I'm missing?
Thanks
Bo

A_trav  VAR GPIO.0          'Travel encoder A  input
B_trav  VAR GPIO.1          'Travel encoder B  input
A_man   var GPIO.2          'Manual Encoder A input
B_man   var GPIO.3          'Manual Encoder B input
P_out   var GPIO.4          'Pulse output to motor
D_out   var GPIO.5          'level output for direction                               
Dir         VAR bit            'Direction
Scratch     var byte            'dummy byte
Old_Bits    VAR BYTE
New_Bits    VAR BYTE
TravEncOld  var byte            'TRAVel Measurement ENCoder
TravEncNew  Var byte            '
ManEncOld   var byte            'MANual input ENCoder
ManEncNew   var byte            '
             
P_out = 1                   'servo I/P = LO pulse, start HI 
 
INTCON = %10001000          'GLOBAL ON, GPIO Int ON
CMCON =  7                   'Comparator off, Digital I/O
OPTION_REG = %00000000      'GPIO Pull-up Enabled
TRISIO = %001111 
WPU = %000111               'pull-ups 0-2 (3 added on board) 
IOC = %001111               'Int On Change GPIO 1-3
ANSEL = 0

INCLUDE "DT_INTS-14-0.bas"     '..-14-0 = ALL Banks REM'd 

ASM
INT_LIST  macro    ; IntSource,    label,  Type, ResetFlag?
        INT_Handler    RBC_INT,  _EncChg,   ASM,  yes
    endm
    INT_CREATE                   ; Creates the interrupt processor
    INT_ENABLE   RBC_INT         ;RB Port Change Interrupt
ENDASM                                           

Old_Bits = GPIO & (%001111)                 'Get initial inputs

Main:
         
GOTO Main

'---[RBC - interrupt handler]---------------------------------------------------
EncChg:
    New_Bits = GPIO & (%001111)                'Get inputs
    TravEncNew = New_Bits & (%000011)          'strip New Travel encoder
    TravEncOld = Old_Bits & (%000011)          'Strip Old Travel Encoder
    if TravEncNew = TravEncOld then ManEnc   ' If no chg -> Manual Encoder
    Dir = TravEncNew.1 ^ TravEncOld.0            'Check direction
    D_out = Dir                                  'Direction LEVEL out
    if Dir = 1 then                              'Only travel 1 direction
    pulsout P_out,20                             'drive servo controller 
    Endif                                'Controller is STEP/DIRECTION I/P
    goto DoneRotEnc                      'skip Manual Encoder
         
ManEnc:            
    ManEncNew = New_Bits & (%001100)           'strip Manual Encoder
    ManEncOld = Old_Bits & (%001100)
    Dir = ManEncNew.3 ^ ManEncOld.2           'Direction of Manual input
    D_out = Dir
    pulsout P_out,20                        'Pulse for either direction

DoneRotEnc:
     Old_Bits = New_Bits                    'reset reference 
     Scratch = GPIO                         'read GPIO to clear mis-match
@ INT_RETURN