Unpacking a PICkit 2 Programmer/Debugger

[Bruce]

Hi Anand,

When you create a variable for a port like PORT VAR PORTB or PORT VAR GPIO, all you're
doing is creating an alias to the port. It doesn't create a variable in RAM like it would for
something like X VAR BYTE.

Look at the screen capture attached. Check out the address for _PORT, GPIO, _X and _Y.

X and Y are variables in RAM. _PORT is just another name for the physicall address of GPIO.
It's not a variable created in RAM. Just an alias to the port address.

Running animations in MPLAB for PBP programs is a bit different than using it with assembly.

If you run something like what's shown in my screen capture, and hit animate, it will show
the green cursor on each line as it executes. Now insert a PAUSE 1 just after PORT = X.

When it lands on the PAUSE 1 it calls the PBP library routine, so the library window opens
and you don't see it execute the PAUSE 1 in the BASIC source window. It's only going to
show inline type commands. Calls to PBP library functions aren't shown in the source code
window. That's why the library window pops up.

Using MPLAB with PBP takes a bit of getting used to, but it's worth the effort.

[ardhuru]

Hi Bruce,

Thanks for the reply; very lucid, as always.

I now understand the issue I'd raised (kind of). What I dont understand yet, although you've touched upon it, is why the animation jumps to the library window whenever it encounters a pause statement. And then doesnt seem to return back to the source window. But, single-stepping seems to work fine.

About the port pins. What you are saying is, I'd have to watch the whole port, and then see the behaviour of the individual pins within; am i right in my understanding?

I must say MCS Plus has really spoilt me; this is one thing about it I miss. But like you said, there seem to be loads of other things in favour of MPLAB that makes the transition worthwhile.

Thanks again.

Anand

[Bruce]

Hi Anand,

But, single-stepping seems to work fine.

Because when you're single-stepping with the Step Over button it steps over the huge
library functions. If you single-step using Step Into, it executes the library function line
by line. Step Over runs the whole library function immediately returning to the next PBP
BASIC statement.

Animation works similar to Step Into - so you lose the green animation cursor when a call
to a library function is made.

About the port pins. What you are saying is, I'd have to watch the whole port, and then see the behaviour of the individual pins within; am i right in my understanding?

Yep. You can watch the port or the alias you've created, but you're still essentially
watching the same thing since the alias is just another name for the same register address.

I must say MCS Plus has really spoilt me; this is one thing about it I miss. But like you said, there seem to be loads of other things in favour of MPLAB that makes the transition worthwhile.

MCS+ is a great little program, but once you get the hang of using MPLAB/MPSIM with PBP
you'll never look back.

MPLAB has a lot of things MCS+ doesn't like the stop watch, logic analyzer, and advanced
features like register injection. You can setup stimulus files to send analog values to A/D
inputs, simulate external switches on pins, and a lot more.

It goes way beyond just watching the animation cursor & viewing register values...;o}

[Ioannis]

MPLAB has a lot of things MCS+ doesn't like the stop watch, logic analyzer, and advanced
features like register injection. You can setup stimulus files to send analog values to A/D
inputs, simulate external switches on pins, and a lot more.

By the way are there any tutorials on these?

Ioannis

[Bruce]

Hi Ioannis,

None that I'm aware of. I'll put one together.

[Bruce]

Here's a complete PBP application showing how to use several of the cool features built
into MPLAB/MPSIM with PBP.

You can run this without even owning PBP, but you can't make changes or re-compile
without PBP - obviously, and you will want to create a directory on drive C as follows -
C:\PBP\SIMTST to install these files in.

If you do own PBP, and it's in C:\PBP, then create the directory as shown above, and unzip
all files into that directory.

What you'll need:

Download & install MPLAB 8.15a. This is the latest/greatest version that supports PBP until
MeLabs makes a few changes. And don't bother asking for help if you're using an earlier
version of MPLAB since this was done with version 8.15a...;o}

You can download 8.15a from the link below;
http://ww1.microchip.com/downloads/e...plab_v815a.zip

Now follow the instructions from MeLabs website on installing MPLAB at the link here;
http://melabs.com/support/mplab.htm for your operating system.

TIP: Anyone that owns the Microchip C18 compiler, that has installed the latest/greatest
version, or anyone that might have installed another program that installs a new version of
MPASM assembler, here's something to look for;

When installing some other program that includes itself in your path statement, it may
C18 does install its own entry before entries that were previously dropped in
your path statement when installing MPLAB.

If that's the case, you may end up with error messages when you try compiling your PBP
program code stating it can't locate .COD files. If you see this, then edit your path
statement placing the PBP & MPLAB entries first - like this;

C:\PBP;C:\Program Files\Microchip\MPASM Suite;c:\mcc18\mpasm;c:\mcc18\bin, blah,
blah.

I ran into this problem after updating C18 to the latest version, and it was a HUGE pain in
the butt to find/fix. MPLAB showed MPASM 5.22 on-screen, but the .LST file showed it was
actually assembled by a much newer version 5.30.01 assembler, which was installed in my
MCC18 directory. A BIG bug to watch out for. MPLAB pops up an MPASM assembler screen
indicating it's using 5.22, but it's really assembling with the 5.30.01 MPASMWIN.EXE in
another directory, so you've been warned...;o}

Moving on:

Once you have MPLAB version 8.15a installed, and these files unzipped into your
C:\PBP\SIMTST directory, you're ready to go.

Start MPLAB. Click Project >> Open, and find C:\PBP\SIMTST\SIMTST.MCP to open this
project.

Click the Step Into button once. If the Watch window doesn't show a value of 00000001
on PORTB, then click on the Stimulus window > Fire button next to RB0. Then click the
Step Into button once more. Now you should see in the Watch window PORTB = 00000001.

Next click the Run button. It will sit & spin now until you click the > Fire button again in
the Stimulus window.

Once you click the Stimulus window > Fire button, it will stop on the breakpoint at the
ADCIN command, and display the pulse stream output on RB1, and the RB0 switch input
pulse in the logic analyzer window.

Next click the Stimulus > Fire button again, then Step Into, and make sure it shows PORTB
00000001 in the watch window again, then click the Run button. You should see the simulated
A/D value passed from the Stimulus Register Injection file ADSTIM.TXT shown in the
Output window under SIM Uart1.

Now comment out the WHILE Switch WEND code, recompile, and just keep pressing the Run
button to see the difference.

Yeah, I know, it's not a complete tutorial, but it does help to show some of the cool MPLAB
& MPSIM features you can work with in PBP.

When I can find the time, I'll work-up a complete tutorial for this, including setup & extra
info on our website and post a link to it here.

[ardhuru]

Hi Bruce,

Okay, that pretty much puts things in perspective. Wouldnt have been able to do the switch without all the inputs I got.

Thanks,

Anand

[Ioannis]

Hi Bruce. Thanks a lot for the quick tutorial!

What if there is already installed the 8.30 version of the MPLAB? Will be any problem with the latest (greatest?) version?

Ioannis

[Bruce]

See the first section here http://melabs.com/support/mplab.htm for info on using PBP with
MPLAB version 8.20 or later.

MeLabs is working on it, but it's not ready yet. If you want to use MPLAB with the latest
version of PBP, you'll need to install MPLAB version 8.15a or earlier.

[ardhuru]

Been making a lot of progress, Bruce.

Now I have a question again.

When using the simulator, my switches (which in hardware have a pull-up) show to be low; how can i change that so that I could use the stimulus to trigger these?

Regards,

Anand

[Ioannis]

See the first section here http://melabs.com/support/mplab.htm for info on using PBP with
MPLAB version 8.20 or later.

MeLabs is working on it, but it's not ready yet. If you want to use MPLAB with the latest
version of PBP, you'll need to install MPLAB version 8.15a or earlier.

Well, I asked because 1. did not read the mentioned article by Melabs and 2. I run your tutorial with no problems. I did not though compiled yet any program in 8.30...

Ioannis