Code Issue? - Pin Labels

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- 12th July 2006, 08:50
jamie_s

Code Issue? - Pin Labels

For some reason the following code has no effect on outputs due to the pin labels:

Code:

InpA VAR PortB.4 InpB VAR PortB.5 InpC VAR PortB.6 InpD VAR PortB.7 LedA VAR PortA.2 LedB VAR PortA.3 LedC VAR PortA.4 LedD VAR PortA.5 RlyA VAR PortA.6 RlyB VAR PortA.7 RlyC VAR PortA.0 RlyD VAR PortA.1 StatusA VAR byte ' Port A Status Flag StatusB VAR byte ' Port B Status Flag StatusC VAR byte ' Port C Status Flag StatusD VAR byte ' Port D Status Flag CurrentPort VAR byte ' Current Port StatusA = 0 StatusB = 0 StatusC = 0 StatusD = 0 LedA = 0 LedB = 0 LedC = 0 LedD = 0 CurrentPort = 1 Goto SetActivePort checkports: If InpA = 0 then pause 50 If InpA = 0 then StatusA = 0 Low LedA endif Else StatusA = 1 High LedA endif If InpB = 0 then pause 50 If InpB = 0 then StatusB = 0 Low LedB endif Else StatusB = 1 High LedB endif If InpC = 0 then pause 50 If InpC = 0 then StatusC = 0 Low LedC endif Else StatusC = 1 High LedC endif If InpD = 0 then pause 50 If InpD = 0 then StatusD = 0 Low LedD endif Else StatusD = 1 High LedD endif

If i Use the following:

Code:

Goto SetActivePort checkports: If portb.4 = 0 then pause 50 If portb.4 = 0 then StatusA = 0 Low PORTB.3 endif Else StatusA = 1 High PORTB.3 endif If PORTB.5 = 0 then pause 50 If PORTB.5 = 0 then StatusB = 0 Low PORTB.2 endif Else StatusB = 1 High PORTB.2 endif If PORTB.6 = 0 then pause 50 If PORTB.6 = 0 then StatusC = 0 Low PORTB.1 endif Else StatusC = 1 High PORTB.1 endif If PORTB.7 = 0 then pause 50 If PORTB.7 = 0 then StatusD = 0 Low PORTB.0 endif Else StatusD = 1 High PORTB.0 endif

it seems to work fine,
is there anything obvious that i have missed?
- 12th July 2006, 15:24
mister_e

Or i'm Blind OR i'm stupid.. i don't see any reason why it shouldn't work. I use PORT alias every day and never had issue with.

what are you using
PIC:
PBP version:

what else is bellow your code, you use a goto at the top. How you acces to the Checkports?
- 12th July 2006, 16:14
paul borgmeier

In the second program, the HIGH and LOW commands automatically make the pins outputs – you have not set them in the first to output. Add

Code:

TRISA = 0 ' make all PORTA output that can be outputs ' (check datasheet depending on your PIC)

to the first.

In the second program, you are changing PORTB pins and in the first, PORTA pins. Most PICs default PORTB to digital but many default PORTA to analog. Without knowing what PIC you are using, it is hard to say if this is the issue. Look at this link from MELABS for help on this latter issue. (Pins must be set digital to use them in your manner)

http://www.melabs.com/support/mcu_hints.htm

Good Luck,
Paul Borgmeier
Salt Lake City, Utah
USA
- 12th July 2006, 16:19
mister_e

yeah but.. Both code use the High LOW statement... one use the PIN alias, not the other.

I agree with the possibility of the analog stuff on every port, but.. it doesn't explain why the PIN alias don't work but the direct HIGH PORTB.x work ... at least it doesn't make sense to me...

OK at the begining is the TRIS is not set, the following lines..

Quote:

LedA = 0
LedB = 0
LedC = 0
LedD = 0

won't do anything for sure unless LOW LEDx is used.

Also we don't know if external pull-up resistor are used.. so that may cause some oddity, and so on ;)
- 12th July 2006, 16:28
paul borgmeier

Quote:

Originally Posted by mister_e

Both code use the High LOW statement...

Wow, coffee please, I missed the scroll bar his code insert on the first program and had not scrolled down to see the rest of his code.

You are right, we are left with the analog issue as a possible problem. As Steve asked, what PIC and what PBP version?

Paul