Hello, i have coded a bit of code. It should read the portb inputs and hold the porta 2 low for 100ms if the b port was high, or high for 100ms if the portb was low. And it should continue and check every potb pin. Put for some reason it just switches on porta 2 if portb 4 is low. It doesn't continue to other ports.

Any help is mostly welcome!

 

Just a few things here.

1) the btfss f,d (from the any pic data sheet) stores f as a seven bit adderss and b as a three bit
constant. Not knowing what uC you are using you should get a warning about truncation when you compile it.

2) You are using a goto SendBit and then a return from that. Need to use a call or you are going to get
stack overflow and the program will not work correctly.

try that sould fix it.
kingpin094

 

I'm using a pic16f628. I fixed the call/goto issue. But I don't cuite understand your first point. Do you mean that I can't use

because it stores it in a wrong format? So i have to approach the problem from a different view and rewrite that part of the code?

This is the warning i get:

74 : Argument out of range. Least significant bits used.

As I understand this it shouldn't have any difference as long as the value doesn't exced 7. And it "doesn't" because it's reseting it to zero before it can read it with an 8 stored.

 

You're looking at the wrong line, that one was fine - this is the one which is wrong!.

You don't give any indication of what Bit_Temp is, but I'm presuming it's a variable - you can't use a variable in this way - BTFSS requires a constant, between 0 and 7.

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Yes Bit_temp is a variable. So it is not possible to use a loop to read all the pins? I have to read all the pinns independently. So much for my attempt to do a bit of a 'better' code

Ok thanks for the help. Much appreciated!

Ofcourse if it is possible to do this in a loop, i'd be glad to know how.

Here's the whole code, if intrested.

Attached Files

code.txt (1.4 KB, 32 views)

 

You can do it in a loop by reading the port to a register, then shifting the register bit by bit in to CARRY, and checking that. If you check my tutorial RS232 transmit routines they do this same procedure to transmit a byte in W.

However, checking each pin with a BTFSS would only take 16 lines, and execute considerably faster (if that was a concern?) - plus it gives the added advantage of easily allowing seperate routines for each pin.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk