Wouter,

Yes, bootloaders are neat and quite 'kewl', but I worry that someone
might manage to overwrite the bootloader code, and end up with a
non-working board. Since the PCB design uses a TQFP PIC, it's a bit
tricky to replace! I'd much rather put some hardware on the board to
program the PIC from any state.

I'll do some more Googling....

Thanks, Peter Moreton


-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Wouter van Ooijen
Sent: 20 February 2004 14:13
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC:] PIC 18F programmer circuit/software?

> I'm working on a design for a PIC18F452 based board that can be
> programmed in the field, by folk who do not have the standard
> Microchip
> tools, such as a Picstart+ or an ICD-2. I don't wish to use a
> bootloader, since this would require the user to have access to a
> pre-loaded PIC, so I'm looking around for a simple circuit to
> build into
> my PCB to enable a blank PIC to be loaded with a .HEX file or similar.

So you want a programmer build into your circuit. Depending on the
interface (serial, parallel, USB) and the programming type (HVP, LVP)
there are various options. Just look around for DIY programmers.

Maybe you should reconsider your aversion to bootloaders. Bootloader
hardware can be very simple (see my ZPL) and the users have to buy their
PICs somewhere, so why not from you (or me :)) pre-loaded with a
bootloader?

Wouter van Ooijen

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