Origa.me

At last, I finally enter the exciting world of Microcontrollers. If it's any use to anyone out there, Byron Jeff's Trivial LVP programmer actually worked very well for me. Here's mine:

My PIC of choice for the purposes of learning and experimentation is the 16F628 (being the more affordable successor to the 16F84). All the parts for the programmer (except the parallel connector and USB lead which I salvaged from old computer gear) came to just over £1.00 not including the small bits of strip board and equipment wire. The USB lead, in case you're wondering, is to supply the regulated 5V power supply required by the programmer.

Assembly was easy enough. Getting it to work took a while and I almost gave up and trundled down to Maplins for one of their kits a couple of times. Abject poverty being the great motivator that it is, however, I kept plugging away and eventually got it running. The problem I ran into was with Windows XP's I/O API, which doesn't work very well with these kind of devices apparently, because of their sensitivity to timing. So, if you're getting verification failures (eg: 'verify failed at address 000h'), here's my winning combination:

• Byron Jeff's Trivial LVP programmer
• David Tait's FPP PIC programming software for Windows
• Either DirectIO or LoadDrv (or both; I forget) or GiveIO. I really don't know which one finally solved the problem for me so try them until something works - it was definitely one of them

I would have liked to have used my little Linux system as the XP machine is really only kept for one particular work client and I hate installing new stuff on it in case it goes all flakey on me. Sadly, Ubuntu refused to detect my Parallel port on that machine and the picprg software recommended for use with the programmer wouldn't use the one I created with mknode so I may have to look to alternative distros in the future if I want to use that machine for development.

As it stands, I'll do the development and assembly code compiling on my Macbook (pre-packaged Mac OSX version of gputils here) and then copy the .hex files over to the XP machine to burn them to the PIC. At least it works!

Of course, all this means that I so far have a rather expensive and complex 'flashing LED circuit'. But that's not quite the point; it's only the first step. Stay tuned!

Update: Following a 'Muppet moment' this evening, it would appear that the LVP programmer works just fine without the external power supply, at least on my desktop's parallel port. How very convenient!

Useful note: If, when using FPP to program your PIC, you get the error "Failed to program config!", it means you're trying to program the config from both your code and the FPP application. Just untick the "Config" checkbox (bottom-right of the FPP interface) and try again.