Me and my PIC
I read about the PIC in a Circuit Cellar Ink. It was a column by Tom Cantrell: Mean and Lean PICin' machines was the title. I was grabbed immediately by this little chip. And Tom also paid attention to the PIC based DSO (also in this section) which showed a 4 trace logic analyzer on screen of a normal 'scope. The PIC DSO was no more than the PIC, some buttons and a cheap DRAM chip.
So I got myself a PIC system. I began with the Parallax development kit. This consisted of two boards. One was
the programmer and the other was a hardware simulator. But neither board had descent ZIF sockets. And the
simulator needed a lot of attention. And the Parallax assembler was not a cross assembler. It was a criss
cross assembler. You programmed in 8051 mnemonics and th criss/cross compiler converted this into PIC source
and next into PIC code.
So in 1993, when Memec still resided in Nuenen, I ordered a PICstart 16B development kit from them. This kit was much more robust. It had a very sturdy Aries ZIF socket that accepted all chips. It ran off a 9 Volt DC supply and had it's own 78S40 switcher on board. Communications were by means of a simple serial port.
In the mean time I did some PIC programming. But my attention also changed to other architectures which -at the time- were better suited for my needs. But lately, Microchip has published many new application specific designs. It might be time to return to home. This series of pages is about that journey.
Project on the way home
Below you see the unpaved road home. Each section is a small description and many topics are related. Have fun
while looking how my road home can help you out on your journey to the future.
If you want to see more of a particular topic, select it in the navigator frame on the right. This frame does not contain significant links to keep the maintenance easy.
Improved JDM programmer
The JDM programmer is like a female athlete. Her body is trained to do just the one sport she prefers. Muscles
and bones. Not more. Not even femininity. An olympic machine that's hard to improve.
Same with the JDM programmer: you cannot make simple modifications. I took the liberty to add some fat to the JDM programmer: ImJDM was born.
PICprog or JDM programmer
One of these programmers is the JDM programmer, designed by Jens D Madsen. Please visit his website at http://www.jdm.homepage.dk and read all about the hardware and the associated software. On this page, you see his original design and the original circuit drawing. Plus my redrawn circuits and explanations about how it works.
Among the members of the WISclub, the JDM programmer is a returning topic. So after todays revisit of the JDM hardware I felt forced to dig into the design and see if I can understand it or not. And possibly improve it.
It took me some time to find one, but now I have a disassembler for the PIC 16C55 that is used in this project. I first assembled the digscope.src file that Parallax made for this project. I assembled the source into digscope.obj, which I ran through the disassembler, to make digscope.asm. And it worked!
You can download the disassembler from this site. I did not make this disassembler myself. Timo Rossi did this
fine work. I merely grabbed it off the web and I forgot from which site. But as of now, you can get if on this
site as well. Both compiled and in source format. The name of the disassembler is 'pic12dis'.
I compiled the C-source with the POWER C for DOS/Windows, so you can run it together with your older PIC tools.
A few months ago I got my PICstart 16B programmer back and this triggered some thoughts, like how to use if
from DOS or even from Linux.... Yummy. Programming PIC's from Linux. That can already be done with many
programs. There are even programs that run with the successor of the PICstart line of programmers.
So I decided to see if I could revive the PICstart. DOS is not an option anymore. I got used and addicted to Linux. I keep pressing the Tab key (without any results) and the slashes also run the wrong way. So now I want to try and see how far I get with writing Modula-2 sources to control the MicroChip PICstart 16B programmer board.
The DigiScope was a project by Parallax INC in the United States of America when they came out with their initial seris of PIC related projects. Among them were a programmer and a debugger, in real hardware. The programmer came with good documentation and a cross cross assembler: you wrote the sourcecode in a language similar to 8051 assembly language and the Parallax assembler then made PIC object code out of it.
To draw attention from the media, they designed this digital storage oscilloscope based on a PIC 16C55. Check out what you can do with a 20 MHz PIC with just one KB of program memory.
Page created February 2006,
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