New At PIC's, need some help with code

[SOHCKing03]

Thanks for the replies...

I think I will test out a code I created using some of the elements from the code you guys gave me...

Hopefully it'll work and I can get this thing going...

-Brad

[SOHCKing03]

Okay well I will use the code from the link Sayzer gave me...

I am making an LED Underbody Kit though and so one PIC will control the front left, one will control the left side, one will control the the back left, and the same for the right side. So I will need my PIC's to communicate. When the last LED on the front left is turned on I want the side to start sequencing and same goes for the transition from side to back.

To do this will I have to set the final output on the front left to go high and then have it connected to an input on the side PIC? That way I could tell the side PIC not to do anything until that input receives a "high" signal from the other PIC. I could do that correct? If so, how would I program it?

Thanks again for all your help guys.

-Brad

[sayzer]

If I understood correct, this should be it. Just an example though.

Wait:

IF PORTA.1 = 1 THEN GOTO Loop
'This is the pin you get the input signal from the other PIC.

GOTO Wait


Loop:

'Your loop code should be here....
'When the last loop index is achieved, 
'you will HIGH a pin to activate the next PIC
'and you will go back to "Wait"


GOTO loop

[SOHCKing03]

Here is the code I came up with...

------------------------------------------------------

SYMBOL PORT_PIN = PORTA
X VAR BYTE ' For loop & bit index pointer

Wait:

IF PORTA.1 = 1 THEN GOTO Main 'checks if input recieves high signal
GOTO Wait

On:

ADCON1 = 7 ' All digital
PORTA = 0 ' Clear all port pins
PORTB = 0
PORTC = 0

TRISA = 0 ' Make them all outputs
TRISB = 0
TRISC = 0

FOR X = 0 TO 23
PORT_PIN.0[X] = 1 ' Set all porta, portb, and portc pins high
PAUSE 200
NEXT X

GOTO Off

Off:

ADCON1 = 7 ' All digital
PORTA = 0 ' Clear all port pins
PORTB = 0
PORTC = 0

TRISA = 0 ' Make them all outputs
TRISB = 0
TRISC = 0

FOR X = 0 TO 23
PORT_PIN.0[X] = 0 ' Set all porta, portb, and portc pins low
PAUSE 200
NEXT X

GOTO On

---------------------------------------------------

My only question now is, how do I set PORTA.1 to be an input? In my code I set all PORTA pins to be outputs. Is there a way I can set just PORTA.1 to be input?

As always, I appreciate your help.

-Brad

[sayzer]

1. You first need to set the TRIS register for a port. Having TRISA = %00000000 makes all pins output. From right to left they are arranged as porta.0 to porta.7. (F877 has 6 pins on PORTA). If you want to make one of them an input, say you need PORTA.1 as input, then you state TRISA = %00000010. Now, all of them are outputs except for PORTA.1 (also for some PICs, you need to watch for MCLR pin which is an input-only pin).
OR, you can just say INPUT PORTA.1

2. You should keep all registers at the beginning. No need to put them into each subroutine.

3. ON is a reserved word. Thus, you can not use it for another purpose.

4. In your code you have "goto Main" but there is no Main. I think you meant "goto ON", but since you can not use "ON", just change ON to Main.

5. For the FOR loop you have, you will not have 8-bits on PORTA. Thus you need to have a look at there. Check Bruce's example on the link above.


Check the datasheet of the PIC you will use. Check which pin can be used as an input-only and/or output-only etc.

Also, check how many pins you have on each port.


----------

------------

[SOHCKing03]

Okay so then here is an updated code:

'----------Code for the Front Left, Front Right, Back Left, and Back Right

SYMBOL PORT_PIN = PORTB
X VAR BYTE ' For loop & bit index pointer


ADCON1 = 7 ' All digital

PORTB = 0 ' Clear port pins

TRISB = 0 ' Make them all outputs

Main:

FOR X = 0 TO 7
PORT_PIN.0[X] = 1 ' Set all pins high
PAUSE 200
NEXT X

GOTO Off

Off:

ADCON1 = 7 ' All digital

PORTB = 0 ' Clear port pins
PORTC = 0

TRISB = 0 ' Make them all outputs
TRISC = 0

FOR X = 0 TO 7
PORT_PIN.0[X] = 0 ' Set all pins low
PAUSE 200
NEXT X

GOTO Main

'----------Code for Both Sides

SYMBOL PORT_PIN = PORTB
X VAR BYTE ' For loop & bit index pointer


ADCON1 = 7 ' All digital
PORTA = 0
PORTB = 0 ' Clear port pins
PORTC = 0

TRISB = 0 ' Make them all outputs
TRISC = 0

Wait:

INPUT PORTA.0
IF PORTA.0 = GOTO Main

GOTO Wait

Main:

FOR X = 0 TO 15
PORT_PIN.0[X] = 1 ' Set all pins high
PAUSE 200
NEXT X

GOTO Off

Off:

ADCON1 = 7 ' All digital

PORTB = 0 ' Clear port pins
PORTC = 0

TRISB = 0 ' Make them all outputs
TRISC = 0

FOR X = 0 TO 15
PORT_PIN.0[X] = 0 ' Set all pins low
PAUSE 200
NEXT X

GOTO Main

-------------------------------------------------

How does that look? For the front and back ones I only need 6 outputs but I need 16 for the sides. I hope I did that INPUT thing right. I assumed that PORT_PIN would still equal PORTB since I'm only using PORTA for the INPUT. Did I do everything correct? Also, I am using a 16F876 so all PORTB and PORTC pins can be outputs, however PORTA.6 and PORTA.7 are unimplemented so that is why I am starting with PORTB.

Thanks again.

-Brad

[mister_e]

IF PORTA.0 = GOTO Main

there's a missing value in that one, 0 or 1

Also, as you're using PORTB and PORTC, there's no special need to use the array method. Just use
HIGH x (from 0 to 15)=> refer to section 4.11 of your PBP manual

something like

X VAR BYTE ' For loop & bit index pointer
ADCON1 = 7 ' All digital
    '   
    ' Clear portB&C pins
PORTB = 0 
PORTC = 0 
    '
    ' Make them all outputs
TRISB = 0 
TRISC = 0
    '
    ' Set PORTA.1 as input
TRISA.1=1
    
Main:
     FOR X = 0 TO 7
         HIGH X ' Set all pins high
         PAUSE 200
         NEXT X
Off:
    FOR X = 0 TO 7
        LOW X ' Set all pins low
        PAUSE 200
        NEXT X

    GOTO Main