switch on a led depending on the switch state (using picbasic and pic16f877)

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pouchito

New Member

• Jun 7, 2007

• #1

Hi all,

i wrote a very simple code but it did not work

i want to turn on a led if the switch is on

this is the code:

TRISA = $ff
TRISB = 0
CMCON=7

main: if PORTA.1=1 THEN
PORTB.1=1
delay_ms (1000)
ELSE PORTB.1=0
END IF
GOTO MAIN

end.

and it did not work, i put the input on portb.b instead of the porta.1, it worked but i need to use the port A as input .

i think my problem is that i did not specify that i need the portA to be digital and not analog? is that right ?
if yes, how ?
please help

 

Last edited: Jun 7, 2007

Norlin

New Member

• Jun 7, 2007

• #2

think it's ANSEL=0 to make it digital
also, your if statement should always return true, or perhaps not in the language you're using, I'm used to C where we'd do if x==1 to test to see if x is 1, whereas x=1 will place 1 in x and always return true on success

 

P

pouchito

New Member

• Jun 7, 2007

• #3

unfortunately, the picbasic did not understand what is ANSEL=0

 

P

Pommie

Well-Known Member

Most Helpful Member

• Jun 7, 2007

• #4

Try ADCON1 = 6

Mike.

 

P

pouchito

New Member

• Jun 7, 2007

• #5

Wowwwwwwwww

Thanks A Lot Pommie, It Worked

 

justDIY

Active Member

• Jun 7, 2007

• #6

picbasic has a command, button, which provides an important function "debounce".

 

P

pouchito

New Member

• Jun 7, 2007

• #7

the buton function works without specifying that the porta is digital ?

 

justDIY

Active Member

• Jun 7, 2007

• #8

no, you'll still need to turn off the analog functions on porta, and make sure the TRISA bit for your pin is set to 1 (input)

picbasic should have a directive ALL_DIGITAL = TRUE which turns off any and all analog features, depending on the chip.

 

P

pouchito

New Member

• Jun 8, 2007

• #9

thanks a lot just DIY