Button help

[darklight]

Hey people.

I'm new to microcontrolers and picbasic.
I was just wondering if anyone could help me with switchs.
I can already output leds from portB.

PIC = 16F627

I'm using a programmer / test board (VELLEMAN VM111) to test buttons and leds.

The leds = 6 on portB
Buttons = 4 on portA

Thanks for any help.

[blainecf]

Make sure:

1. ADCON1 = 7 so that your PORTA pins are digital

2. Set the appropriate TRISA.x = %1 for Digital Input

3. Wire a pull-up resistor (10K from V+ to each pin that will sense the switch)

4. Wire each switch, one side ground, the other to the pin from step #3

5. Set up a loop for polling the ports; High (%1) will be normal, and Low (%0) will show when the switch is held closed.

If you're not used to digital signals, it seems weird to ground out a resistor thats hooked to V+, but just accept it.

Regards,

[mister_e]

ADCON1=7 have nothing usefull to do with the 16F627 but compilation error. There's no ADCs in the PIC16F627, just analog comparator.

CMCON=7

[homebrewer]

ADCON1=7 have nothing usefull to do with the 16F627 but compilation error. There's no ADCs in the PIC16F627, just analog comparator.

CMCON=7

I'm a beginner too. I had also problems to query PORTA. The tip with CMON=7 was the solution. Steve, thank you very much!
_______________
Regards
Johann

[Archangel]

Attention fellow newbies:
Here's what I learned the hard way, twice!
When your button code calls a LABEL,
put that labeled code in the very next line after your button code,
or you get nasty error codes assuring you that it is not really a label.

I ran into this in a program with several sub routines and several buttons
and the only way it would compile was if I put the subs directly after the button.

[flotulopex]

I can't make it work with the BUTTON command.

So I tried the other way and use the simple IF..THEN command.

But again, I have the same unexpected result. The Led starts to blink when I press the button. As I release the button, it never "toggles" as I want it to do.

Since this program behavior is the same in both cases (BUTTON and IF..THEN commands), I assume something is wrong with some register settings.

I was thinking about a bouncing problem, but I'm not sure about that.

Here is my code; where do I miss something?

'PIC 16F88
'Button is on PORTB.3 (Pin 9) Pressed = 0V
'Led is on PORTB.4 (Pin 10)

OSCCON = %01100000 'Internal RC set to 4MHZ
TRISB = %00001000 'RB3 is an Input, all others are Outputs
'----------------------------------------------------------------

' IF..THEN
MAIN:
IF PORTB.3 = 0 then SWITCH_LED
goto main

SWITCH_LED:
pause 100 'Debounce
toggle PORTB.4
goto main

end

'----------------------------------------------------------------
' BUTTON

'BVar var byte
'BVar = 0
'
'MAIN:
' BUTTON 9, 0, 255, 255, BVar, 0, SWITCH_LED
' goto main
'
'SWITCH_LED:
' pause 100 'Debounce
' toggle PORTB.4
' goto main

END

[med2007]

On the side, could you tell me the correct syntax to poll portb in a for..next loop?
viz
FOR i = 0 to 7
IF portb.[i]=0 THEN GOSUB alarm
NEXT i
This doesn't work and I can't find the answer in the book

Make sure:

1. ADCON1 = 7 so that your PORTA pins are digital

2. Set the appropriate TRISA.x = %1 for Digital Input

3. Wire a pull-up resistor (10K from V+ to each pin that will sense the switch)

4. Wire each switch, one side ground, the other to the pin from step #3

5. Set up a loop for polling the ports; High (%1) will be normal, and Low (%0) will show when the switch is held closed.

If you're not used to digital signals, it seems weird to ground out a resistor thats hooked to V+, but just accept it.

Regards,

[skimask]

On the side, could you tell me the correct syntax to poll portb in a for..next loop?
viz
FOR i = 0 to 7
IF portb.[i]=0 THEN GOSUB alarm
NEXT i
This doesn't work and I can't find the answer in the book

http://www.picbasic.co.uk/forum/showthread.php?t=544

[med2007]

Thanks for the link...so my syntax should be?

FOR i = 0 to 7
IF portb.0(i) = 0 THEN GOSUB alarm
NEXT i

I'll give it a whirl.
Rgds
MED2007