Quad Encoder Problem

[RossWaddell]

Hi,
Just realised I misunderstood you a bit. I thought you were trying to use the 12F1840 with this code, then I realised you're actually using the 16F1825 that's in the schematic...duh...

Anyway, I've breadboarded a 12F1840 (don't have any 18F1825) and now have an encoder counting properly, sending the count over the USART. I simulated the EEPROM write by adding a PAUSEUS xxx in the handler and found that the limit for correct response - in my case - is around 500us. Anything above that it starts missing edges, coutning the wrong way etc.

So, if the EEPROM write takes even remotely as long as 10ms then that is most likely the issue.

/Henrik.

Ok, it works now - mostly. What's weird is the 'MotorRPM' as displayed on the LCD jumps by 3-4 (i.e. current setting is '120' and then one click of the encoder makes it '124'). The only thing I did was comment out the WRITE line (and the PAUSE 100 too, of course). Sometimes, it misses incrementing the click completely (although only rarely).

Does this have something to do with the comparison logic?

' ***************************************************************
' [IOC - interrupt handler]
' ***************************************************************
RotEncAdjust:
    New_Bits = PORTA & (%00000011)
    IF (New_Bits & %00000011) = (Old_Bits & %00000011) Then DoneRotEnc

    RotEncDir = New_Bits.1 ^ Old_Bits.0
    IF RotEncDir = 1 Then
        ; CW rotation - increase speed but only to a max of 'MaxDuty'
        IF MotorRPM < MaxDuty then MotorRPM = MotorRPM + 1
    Else
        ' CCW rotation - decrease speed to a min of 0
        IF MotorRPM > 0 Then MotorRPM = MotorRPM - 1
    EndIF

;    WRITE EE_MotorRPM, MotorRPM
;    pause 100

DoneRotEnc:
    Old_Bits = New_Bits
    
    IOCAF.0 = 0      ' Clear interrupt flags
    IOCAF.1 = 0

@ INT_RETURN

[RossWaddell]

Another weird thing - If I comment out this line:

' Enable interrupts on RPM control now that motors are fully spun up
INTCON   = %10001000        ' Global int enabled, IOCI enabled, 
                            ' INTF flag bit 0 clr, IOCI flag bit 0 clr
IOCAP.0  = 1                ' Enable positive (rising edge) change
IOCAP.1  = 1                ' Enable positive (rising edge) change
IOCAN.0  = 1                ' Enable negative (falling edge) change
IOCAN.1  = 1                ' Enable negative (falling edge) change
IOCAF.0  = 0                ' Clear interupt-on-change flag
IOCAF.1  = 0                ' Clear interupt-on-change flag

@ INT_ENABLE   IOC_INT      ; Interrupt-on-Change interrupt

and these ones:

' ***************************************************************
' [IOC - interrupt handler]
' ***************************************************************
RotEncAdjust:
    New_Bits = PORTA & (%00000011)
    IF (New_Bits & %00000011) = (Old_Bits & %00000011) Then DoneRotEnc

    RotEncDir = New_Bits.1 ^ Old_Bits.0
    IF RotEncDir = 1 Then
        ; CW rotation - increase speed but only to a max of 'MaxDuty'
        IF MotorRPM < MaxDuty then MotorRPM = MotorRPM + 1
    Else
        ' CCW rotation - decrease speed to a min of 0
        IF MotorRPM > 0 Then MotorRPM = MotorRPM - 1
    EndIF

;    WRITE EE_MotorRPM, MotorRPM
;    pause 100

DoneRotEnc:
    Old_Bits = New_Bits
    
    IOCAF.0 = 0      ' Clear interrupt flags
    IOCAF.1 = 0

@ INT_RETURN

... the interrupts don't seem to fire. And then the button push doesn't work, either (and that's not interrupt driven):

Main:
    ' Check if motor RPM has changed
    IF MotorRPM <> Old_RPM Then
        Old_RPM = MotorRPM
        GOSUB ChngMotorHPWM
    EndIF   
   
    TimeCnt = 0
	While ButtonPress = 0
	    TimeCnt = TimeCnt + 1
	    Pause 10
	    If TimeCnt > 500 Then BtnAction
	Wend
 
    BtnAction:
        If TimeCnt > 0 and TimeCnt < 200 Then
            PortEngDir = PortEngDir + 1
            If PortEngDir > 1 Then PortEngDir = 0
    
            WRITE EE_PortEngDir, PortEngDir
            #IFDEF USE_LCD_FOR_DEBUG
                HSEROUT [LCD_INST, LCD_CLR]
                pause 5
                HSEROUT ["PortEngDir=", DEC PortEngDir, "  ", 13, 10] ' Send text followed by carriage return and linefeed
            #ENDIF

            GOSUB ReversePortEng
        ElseIf TimeCnt >= 200 Then
            WRITE EE_MotorRPM, MotorRPM_Default  ; restore Default value
        
            MotorRPM = MotorRPM_Default
        EndIf
 
    GOTO Main