PicBasic Pro Code Problem

I do not use Basic but program is simple. As I could understand compact written loop code with "For" does not work?

Of course there would be a problems with PicBasic software, btw have you got any diagnostic messages from compiler? Nevertheless try this:

For i=0 to 7 step=1 ' try to determine a step

....your code

NEXT 'do not place i

Maybe it does not need to place i there? I have not any idea what from are composed the different dialects of Basic and how they are working. So do not mind so seriously my suppositions .

Best regards.

Post Script. "i VAR byte" Is it declaration of variable? It's not clear for me concerning byte.

Hi caramba,

I am having a bit of trouble understanding what you are saying, but I very much appreciate you taking the time to answer my post. I think I've made the problem a little clearer in my posts #18 and #19, as well as indicate a plan of action.

I promise that I will come back and let you all know what I find out!

Mike

Saying 'This doesn't work' isn't much help...and is poor reporting/observing of the facts.

What exactly does it do?
Does it initialise ok and light the first Leds...?

I'm not familiar with that particular coding... but my comment still holds good..always supply as much accurat information as possible.... for all we know you might not have a 5v supply!

Del

Hi Mike,

Here is a forum likely to give you better info and answers on Pic Basic Pro problems

http://www.picbasic.co.uk/forum/

Hi Neil,

Thanks for the the tip. I have been there before, but haven't posted this problem there. I think I'll talk to ME Labs tomorrow to find out the reason for it not working and a workaround, if possible. If they can't help me with a workaround, I'll go to the PICBasic forum and post what I need there.

Again, thanks Neil!

Mike

Hi Mike, have you looked at PBP manual from:

http://www.melabs.com/downloads/pbpm304.pdf

and then look at section 4.4 Aliases (page 22), which describes port pin naming, amongst other things

Regards, Neil

Hi,

If you are still having a problem, I'd sugest debugging it outside the loop...

e.g. Simplify.. try just.

i VAR byte
i=1 (or whatever the correct syntax is)
High PORTD.i ' Turn on LED connected to PORTD.0
Pause 50 ' Delay for .5 seconds
Low PORTD.i ' Turn off LED connected to PORTD.0
Pause 50 ' Delay for .5 seconds

This should narrow it down a bit...maybe it's just some peculiarity of the language/interpreter/assembler that maybe doesn't lke port allocations being variables or some thing weird like that.

When in doubt simplify, eventually you will boil it down to the actual line of code that doesn't work...then you can throw the rubber brick at the mointor.

Del

I suspect that "PORTD.0" describes a physical pin on the IC. (through "PORTD.7"). The compiler (assembler) doesn't recognize "PORTD.i" as it is not a physical location.

I suggest that you contact www.microchip.com . They can explain why it won't work, and also give you software ways around it.

Bill

I have questions about your post.

Is it a compiler error or the compiled code won't run in the PIC?

Are your LEDs installed with proper polarity?

Power supply is proper voltage and polarity?

The PIC is properly initialized in the code? As in device type, port DDR, etc. Variables are DIM ed properly as to word, byte or bit?

All of these little things can cause a non working program.

I don't mean to say you are inexperienced or demean your electronic and programming talents but, these little things have driven me over the edge more than once only to return to a project and find it was some little common thing I had over looked. I find my self asking myself "What were we thinking?"

Please, let us all know the result!

blueice

One other thing is to check your delays. If they are too short the LED will flash but too fast for the eye to see it.

Good hunting and stay frosty!

blueice

Hi blueice,

Keep in mind (and I think I made it clearer in my post #5 reply to Del), that there are two sets of code here. They are both supposed to be identical in their functionality.

The first one explicitly & laboriously numbers and commands each pin for the firing of its associated LED. This section of code compiles and programs and runs on the PIC16F877A as expected.

It seemed to me that this code could be condensed using a variable for the pin number and doing a FOR/NEXT loop, which I've done in VB forever (seems like).

So, putting (only) the second section of code in, the compiler chokes when it comes to the "High PORTD.i" line.

That's why I suspect that John (#6), Del (#10) and Sciesis2 (#11) may be right about the physical port not being addressable by a variable.

There must be some way to condense that code though!

We had a trial today at work and I was busy all day, so I didn't have a chance to call MicroEngineering Labs. I'll talk to 'em tomorrow and come back here to let y'all know what I find out.

Mike

Hi Everyone - this is an update. Below is an email I sent to MicroEngineering Labs on 3/3/2008 @ 8:30 EST. I'll post the response as soon as I get it.

Mike

Hello and Greetings,

I purchased PICBasic Pro and assembled all of the parts on the LAB-X1 PCB that I bought from you. The board seems to be working just fine. "Hello World" and "Blink" sample programs work as expected. I am very happy with my purchase.

I have coded the PIC16F887A chip to light the first 8 LEDs (in sequence, in a loop) of the LED bargraph on the LAB-X1 board. Using the HIGH and LOW commands (with pauses in between), and giving these commands for EACH PIN as follows:

loop:
High PORTD.0
Pause 50
Low PORTD.0
Pause 50

High PORTD.1
Pause 50
Low PORTD.1
Pause 50

High PORTD.2
Pause 50
Low PORTD.2
Pause 50

High PORTD.3
Pause 50
Low PORTD.3
Pause 50

High PORTD.4
Pause 50
Low PORTD.4
Pause 50

High PORTD.5
Pause 50
Low PORTD.5
Pause 50

High PORTD.6
Pause 50
Low PORTD.6
Pause 50

High PORTD.7
Pause 50
Low PORTD.7
Pause 50

Goto loop
End

This code compiles, programs, and executes just fine.

Yet when I try to substitute a variable for the pin number, the compiler chokes on the first line of code, giving the following error:

ERROR Line 20: Bad variable modifier: .i.

The code that generated this error is as follows:

i VAR BYTE
FOR i = 0 TO 7
High PORTD.i 'This is LINE 20
Pause 50
Low PORTD.i
Pause 50
NEXT i

Can you tell me why I get this error?

In the code that works, having to explicitly number each pin (and write the line of code that goes with it) seems rather laborious. There must be some way to condense the code. Is there another way to reduce the number of lines of code in a program where the same command on sequentially numbered pins (and looped) is required?

Mike Hogan

Oops, guess I'm not anonymoys anymore!

anonymous

It seems here is specific of PicBasic as said John, Del and others. The only way (if it possible in this version of Basic) to pre-create indexed array of LED states S[8]={"PORTD.0", "PORTD.1", "PORTD.2" ...."PORTD.7"}. Excuse me for some C++ notation as I treated Basic so long time ago. "PORTD.i" is string variable in C. It's remain up to you how you must treat variables in your ProBas program.

Once more else plausible way: Can you gather string variable somewhat like "PORTD."+"i"?

i from integer type should be converted to char type. Sorry for C approach again.

Best regards.

Car.

My last comment means PicBas has to eat construction like this

High S[i]

Pause 50....

hmm.. I'm not sure of that, though you can try it.

Regarding "bad variable modifier" it's just about that in your loop you declared i as integer type, but for command PORTD.i this i should be inserted as char variable (ASCII, for instance 1 in ASCII has code 31 for MSDOS). So you need to convert i to char(string) variable (for example ii) and then put it to your PORTD.ii variable.

If PORTD.I is unbreakable command --- nothing will help, though it looks like Structure.

Kind regards.

Hi Mike,

The condensed version of your code seems as though it should work.

Still some "gotchas" here.

To set a pin or port to an output (or input), set its TRIS register. Setting a TRIS bit to 0 makes its pin an output. Setting a TRIS bit to 1 makes its pin an input. For example:

TRISA = %00000000 ' Or TRISA = 0

sets all the PORTA pins to outputs.

TRISB = %11111111 ' Or TRISB = 255

sets all the PORTB pins to inputs.

TRISB = %11111111 ' Or TRISB = 255

Have you set the TRIS register? Or is this just automatic when a port pin is set to 1 in Picbasic Pro?

There are certain variables that are reserved. Is there a conflict with "i"?

blueice

Hi blueice,

Whenever you use the HIGH or LOW commands, the associated pin is set to an output automatically.

Thanks for the input though!

Mike

I assume you still have the "goto loop" else your "for" loop will only execute one time and end.

Good Luck

Try This!

i VAR BYTE
FOR i = 0 TO 7
High PORTD.0(i) 'This is LINE 20
Pause 50
Low PORTD.0(i)
Pause 50
NEXT i

Cheers!

OK Guys, here's the solution:

CLEAR

i VAR BYTE

TRISD = 0

PORTD = 0

FOR i = 0 TO 7

PORTD.0[i] = 1

Pause 50

PORTD.0[i] = 0

Pause 50

NEXT i

Thanks for all the effort at help with this problem. You guys are great! Now I just need to understand why this works.

MicroEngineering Labs was very quick to answer me; my appreciation (if anyone associated with MELabs ever reads this).

Kudos to all!

Mike

I think you forgot to set PORTD for output:

PORTD=0

I think you forgot to set PORTD for output:

TRISD=0 REM Set PORTD for output

Sorry about the mistake (PORTD=0) posted earlier.

Dear guest,

Please read posts #36 and #37. As I mentioned in post #36, the commands HIGH and LOW AUTOMATICALLY make the designated pin an output.

I show the solution in post #37.

You really should read the entire thread before posting replies.

Mike

Hey Mike in this message (below) you posted some time ago did you get a reason why you cannot index a variable assigned as an LED? Hi Everyone, MY PicBasicPro accepts the following code. (lights 8 LEDs in succession) CLEAR loop: High PORTD.0 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.0 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.1 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.1 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.2 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.2 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.3 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.3 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.4 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.4 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.5 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.5 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.6 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.6 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds High PORTD.7 ' Turn on LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Low PORTD.7 ' Turn off LED connected to PORTB.0 Pause 50 ' Delay for .5 seconds Goto loop ' Go back to loop and blink LED forever End SO WHY DOESN'T THIS WORK? CLEAR i VAR byte FOR i = 0 TO 7 High PORTD.i ' Turn on LED connected to PORTD.0 Pause 50 ' Delay for .5 seconds Low PORTD.i ' Turn off LED connected to PORTD.0 Pause 50 ' Delay for .5 seconds NEXT i Mike

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