A/D problem on 18F2550 ?

Before i get flamed, i have read the data sheet many times, but its perhaps that i am not understanding it !

If i change the Swicth input to say PORTC.1, all works fine, on PORTA.1 it does not.

I am missing something in this code. I have been trying for a day and it is driving me mad !!

Code:

---

Clear
ADCON1 = %00001111
DEFINE OSC 20         
DEFINE LOADER_USED 1

' ---------- [ I/O Definition ] ----------
TRISA = %00000011      ' Set PORTC (0-2 input) rest Outputs
TRISB = %10000001      ' Set PORTB (0)INPUT (1-5)OUTPUTS
TRISC = %01000111      ' Set PORTC (0-2 input) rest Outputs
PORTB = 0

Switch      VAR PORTA.1    ' use a pin with Schmitt Trigger input
RedLED      VAR PORTB.1
X          VAR word
Presses    VAR BYTE
LOOP        VAR BYTE
confirm_flag var byte

Main:
    if Switch = 1 THEN
        WHILE Switch = 1 : WEND
        COUNT  Switch, 1500, Presses
        BRANCHL Presses,[routine1, routine2, routine3]
        GOTO MAIN
    endif
GOTO Main

'--------------
routine0:        ' button was not pressed again
                ' or pressed more than 3 times
GOTO Main

'--------------
routine1:        ' pressed once
    HIGH REDled
    PAUSE 500
    LOW REDled
    GOSUB Confirmation
    if confirm_flag = 1 then gosub flash
Goto main

'--------------
routine2:        ' pressed twice
    FOR X = 1 TO 2
        HIGH REDled
        PAUSE 500
        LOW REDled
        PAUSE 500
    NEXT X
    GOSUB Confirmation
    if confirm_flag = 1 then gosub flash

GOTO Main

'--------------
routine3:        ' pressed thrice
    FOR X = 1 TO 3
        HIGH REDled
        PAUSE 500
        LOW REDled
        PAUSE 500
    NEXT X
    GOSUB Confirmation
    if confirm_flag = 1 then gosub flash

GOTO Main

Flash:
    For loop = 1 to 10
        Redled = 1
        Pause 50
        Redled = 0
        Pause 50
    Next Loop
Return

Confirmation:
    confirm_flag=0
    x=0

    WHILE (x<300) and (confirm_flag=0)

    Pause 10 'check for button every 10ms
    if Switch = 1 then confirm_flag = 1  ' if button pushed then set the flag
    x=x+1 ' increment the pause counter
    WEND

Return

---

Many thanks,

Steve

Well the only pointer i can say

look for ADCON, ADCON0, ADCON1 and/or CMCON register. PORTA can be set as analog i/o by default. So you nbeed to set it to digital.

I thought i have, the register that i thought was applicable was the ADCON1 which has been set to ADCON1 = %00001111.

Are there any others that i am missing.

I thought this was the only one, as if i set the code to:

Code:

---

Main:
    if Switch = 1 THEN
        gosub flash
        endif
GOTO Main

Flash:
    For loop = 1 to 10
        Redled = 1
        Pause 50
        Redled = 0
        Pause 50
    Next Loop
Return

---

When you push the button, it does jump to the Flash routine. So i am guessing it is in digital mode.

I have a pull-down resistor on the input pin, which when the switch is pressed the input line goes to 5v.

I'll keep trying for a solution. Of course it could be my code up the spout !!

Steve

Tissy,

Well, my original comment is still there, but I guess the thought behind it didn't make it through.

' use a pin with Schmitt Trigger input
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