Piklab

Hello Nicolas.

Thanks for the information.

I am using the "EPE Toolkit mk3" [1] from "Everyday Practical Electronics" magazine October 2001. I have the kit version supplied by Magenta Electronics Ltd [2]. I don't suppose that many people are still using this board!

The programming software was specially written by the designer for the board [3] in Visual Basic for Windows. Since I am using Linux, I have written my own programmer software using C and Python.

The system is a tutorial board with LEDs, switches etc, and an in-circuit high voltage programmer. The data and clock connections are rerouted for programming by a 3-channel, 2-way multiplexer which is controlled by the parallel port's D4 (pin 6). The multiplexer switches the PIC between programming and non-programming mode. The parallel port pins are:

D0 data out
D1 clock
D4 program (multiplexer control)
ACK read/verify
D3 reset

The extra "reset" line pulls the PIC's MCLR to 0V. A pulse must be sent to "reset" before "program" is turned on. "Reset" sets MCLR to 0V and "program" switches MCLR from Vdd (5V) to Vpp (12V). This is so that the PIC remains powered up (running the program in its program memory) between programming sessions.

I have tried connecting Piclab's "Power(Vdd)" to the "reset" pin, but I think it sends a steady voltage, not a pulse, so MCLR remains at 0V instead of rising to Vpp

This is the start of the programming sequence in my own software:

INITIALISE
clock off
data out off
prog off (MCLR connected to 5V via multiplexer)
reset off

START PROGRAMMING
reset on (MCLR shorted to 0V via transistor)
reset off (MCLR connected to multiplexer)
prog on (MCLR connected to 12V via multiplexer)

...

send data and clock signals

...

FINISH PROGRAMMING
clock off
data out off
prog off
reset off

As I said before, I am quite happy using my existing programmer software, but I would quite like to see if there might be quick and easy mod to Piclab. Perhaps you could tell me which cpp file(s) sets up the port lines and sends the signals to start programming?

[1] http://www.epemag.wimborne.co.uk/1001.htm
[2] http://magenta2000.co.uk/kits/880.htm
[3] ftp://ftp.epemag.wimborne.co.uk/pub/PICS/ToolkitTK3/

Thanks,
Chris.