Programming 12F683 in QBASIC

[camerart]

Hi,

I can't get a 12F683 PIC to accept inputs. Here is an example of what I've tried.

'03.01.14

'Test 12F683

OSCCON = %01100000 'Internal 4MHz osc
ADCON0 = 0 'A/D off
CMCON0 = 0x07 'Comparators off
ANSEL = 0 'Set all digital
WPU = 0 'Internal pull-ups = off
OPTION_REG = %10000000 'Pull-ups = off, GPIO.2 = I/O, prescaler to Timer1
GPIO = %00000000 'All outputs = 0 on boot
TRISIO = %00100100 'GPIO,0
Config GP2 = Input
start:
If GP2 = 1 Then
GP5 = 1
Else
If GP2 = 0 Then
GP5 = 0
Endif
Endif
Goto start

End

At one time I had a TOGGLE LED to show it was working, and even though the program didn't work properly, did show a change when the input went high.

I copied the top part where is sets up, and have changed it a little!

Cheers, Camerart.

[HenrikOlsson]

Hi,
Well, that code won't even compile with PBP, which compiler are you using?

* The format 0x07 isn't supported in PBP, to write in hexadecimal notation use $07.
* The individual bits on GPIO registers are accessed as GPIO.x not GPx.

Try changing that for starters and see if it makes it better.

/Henrik.

[camerart]

Hi Henrik,

I don't know what PBP means?

I'm using what I know as qbasic, I'm too long in the tooth to change I'm afaraid. I use PICSIMULATORIDE for simulating and compiling, then PICKIT2 for burning.

With the above set-up I can program 16F819 PICs and I've had the 12F683 with a LED flashing, but can't get any inputs.

Cheers, Camerart.

[camerart]

Hi,

I now know what PBP means

Anyway! I got a simple timer working, here is the code I used:

'03.01.14

'Test 12F683

OSCCON = %01100000 'Internal 4MHz osc
ADCON0 = 0 'A/D off
CMCON0 = 7 'Comparators off
ANSEL = 0 'Set all digital
WPU = 0 'Internal pull-ups = off
OPTION_REG = %10000000 'Pull-ups = off, GPIO.2 = I/O, prescaler to Timer1
GPIO = %00000000 'All outputs = 0 on boot
TRISIO = %00001000 'GPIO,0=data in, GPIO,1=IRLED out, GPIO,2,3,4,5 unused

Dim s As Byte 'Seconds

'needs reset>>>>>>>>>>>>>>>>>>>>>>>.

start:
If GP3 = 1 Then
Gosub sequence
Endif
Goto start

End

sequence:
GP5 = 1
WaitMs 200
GP5 = 0
WaitMs 200
GP5 = 1
WaitMs 200
GP5 = 0
WaitMs 200
For s = 0 To 52
WaitMs 1000 '50 seconds
Next s
GP5 = 1
WaitMs 200
GP5 = 0
WaitMs 200
GP5 = 1
WaitMs 200
GP5 = 0
WaitMs 200
s = 0

Return

I noticed on the data sheet, it said "GP3 is only input" so I changed my input to GP3 and it works. I'm sure if I understood better, I could get more inputs though.

Cheers, Camerart

[HenrikOlsson]

Hi,
I'm glad you figured it out!
As you probably know, this forum is primarily targeting PBP (PIC BASIC Pro) from Micro Engineering Labs. Unfortunatley there are differences between various BASIC compilers so what applies to PBP may not be relevant to the compiler you're using.

It's not that the people around here wouldn't want to help just because you're using another brand compiler but you'll most likely get much better help on a forum or newsgroup discussing the particullar compiler you're using.

/Henrik.

[Heckler]

That GP3 has tripped me up more than a few times as I was just learning. That is true, it can only act as an input (or the MCLR, depending on your configuration fuses)

In fact on all the PIC's that I have worked with so far... What ever pin is the MCLR pin can ONLY act as Input or MCLR.
All the other 5 pins can act as either input or output depending on the TRISA register.

Be sure and get (download) the datasheet for any PIC that you choose to work with.
It is essential to refer to as you are setting up and defining the pin functions and other features (timers, A/D, PWM, etc).

The configuration (CONFIG) register is the one that defines the function of that GP3 pin, (and other things like WDT, Brown Out Reset, etc). This register can ONLY be defined at the time you burn the program into the PIC. It can NOT be changed on the fly by your program as it runs. So you must choose how you want the bits in the CONFIG register set and leave them that way unitl you re-program the PIC.

good luck