Author Topic: PIC serial programmer DIY - information overload  (Read 3383 times)

earthtonesaudio

PIC serial programmer DIY - information overload
« on: February 24, 2013, 09:13:58 PM »
I want to use a Linux OS to program a PIC18F14K50 microcontroller.  The computer I'll be using is an ancient Dell notebook with serial and parallel ports.  I'm agnostic about which one to use, but the serial would be preferable in case that comp finally bites the dust and I want to port to another machine.
My budget for the programmer is $0.00 but I do have parts (DB9 connector, passives, transistors, diodes, headers, wire, solder, etc.) so I plan to build my own.

There is a wealth of info about this topic in general, but that's the problem.  Everybody's serial programmer schematic is *slightly* different, and I don't know what will work for this particular chip.
For example, this site has a bunch of programmers I could build and software that supposedly will work with them... but which programmer to choose?

Questions:
1. Building a serial programmer with an external high voltage supply for fuse-setting or whatnot is no problem.  I just don't know if it's what this PIC requires or if such a setup will damage it.  So... low or high voltage?
2. Any other software recommendations?  Something that will run on 1200MHz, 256k RAM, Linux? So far I have found picpgm and SDCC.

potul

Re: PIC serial programmer DIY - information overload
« Reply #1 on: March 05, 2013, 09:37:27 AM »
The tipical simple serial programmer for PICs is the JDM or one of its variants. Low part count and low complexity. You can build it in vero or stipboard if you want.

The only tricky thing is... not all PCs work with it. In the past I had some issues with the serial port of some laptops to make it work. It seems related to the fact that it is taking the power from the serial port.

Good luck!

Seljer

Re: PIC serial programmer DIY - information overload
« Reply #2 on: March 05, 2013, 12:26:59 PM »
I had the same string of bad luck with the serial port. I ended up up using the parallel port to burn a chip to make a USB programmer :)

slacker

Re: PIC serial programmer DIY - information overload
« Reply #3 on: March 11, 2013, 06:06:44 PM »
Nice find on that software, I've been looking for some Linux software on and off for a while, and somehow never come across it. The only other program I found was Pony Prog and that's pretty old and wouldn't compile on my machine, I might have been able to get it to work but couldn't be bothered spending any time on it.

I gave picpgm a try and breadboarded the Olimex PIC-PG2 Programmer linked to on the site, I chose that purely because the schematic was easier to read than the JDM schematic. It seems a bit flaky, only detects the programmer about 50% of the time, which to be fair might be because it's on breadboard connected to a foot or so of serial cable, but it works. Happily programs, reads and erases PICs.
You should be able to use this to program your PIC18F14K50, you might need to tweak it slightly though, according to the picpgm site that PIC needs a programming (MCLR) voltage of between 8 and 9 volts and the programmer provides about 12 volts. You might be able to lower this by using a lower voltage zener for D3, or maybe add a zener clamp across MCLR and GND.
« Last Edit: March 11, 2013, 06:13:23 PM by slacker »