PIC programmer
If you are
constructing a PIC based project like the "Pic-a-Switch" (see RadCom
September-December 2001) designed by Peter Rhodes (G3XJP), you will need a PIC
Programmer.
The PIC
programmer has two parts: the hardware and the software. Connected to your PC,
the hardware part acts as an interface between the PC and the actual PIC chip
package. The software part runs on the PC and delivers the machine code program
on to the actual PIC via the programmer hardware.
The unprogrammed
PIC may be plugged into the programmer hardware itself as in the picture above
(though the ‘in situ’ lead would be removed then). When the program has been
loaded into the PIC you can physically unplug it, taking care not to damage the
pins, and then plug it into your project. Or you can plug the unprogrammed PIC
into your project and then connect a lead between the programmer and your
project (so the PIC socket on the programmer would be empty then). The lead
allows ‘in situ’ programming and avoids transferring the PIC and damaging its
pins.
I used David
Tait’s Topic version 3 design. I found the DOS programmer software and all the
details for constructing the hardware in the topic03.zip file at:
David Tait’s PIC Archive. Topic03.zip also contains debug.exe
(a test program), problems.txt (problems & suggestions), and walk.hex
(a small program).
Peter Rhodes
gives excellent advice on "Etching The Board" in his Pic-a-Switch
article in RadCom October 2001.
To start with,
the programmer would not work with my PC. The debug.exe program came in
useful and showed up a problem reading pin RB7. Problems.txt came to the
rescue and following the suggestion of adding a diode for the SEL line fixed
this. I did not try the suggested extra pull-up resistor. The fix allowed the walk.hex
program to load into a PIC from my old 486 PC via the parallel port. The PC was
running a DOS window under Windows 95 using the topic03.exe software.
David Tait also
offers Windows based programmer software at David Tait’s PIC links . The zip file with the
software shows schematics of all his programmers. He suggests the PMICP
as being very simple – it uses a serial port connection to the PC.
You can write
your own PIC programs or amend existing ones using the MPLAB IDE software
downloaded from Microchip's Development
Tools .
I bought most of
the components for the programmer hardware locally from Bardwell’s in
page
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