Subject: Re: rs232-controller switches
To: Manuel Bouyer <>
From: Gavan Fantom <>
List: netbsd-users
Date: 05/23/2003 11:08:42
On Thu, 22 May 2003, Manuel Bouyer wrote:

> > A minimal PIC programmer shouldn't cost you more than a few dollars if you
> > build it yourself. I use a setup where the main cost is the parallel port
> > connector, running off a 12V supply (readily available inside your PC). It
> > consists of a 5V regulator, 2 transistors, an LED for show, and a small
> > number of resistors. I use it to program a 16F84A, but there's no reason
> > it shouldn't work with other PICs in the range.
> Do you have the shematic somewhere on web ?

Not at the moment, although I do plan to put some pages up.

There are a number of other PIC programmer circuits on the web though. All
you really need is a switchable 12V programming voltage on the _MCLR_ pin,
and then wire the clock and data pins to the parallel port. The only
complication is that the data pin is bidirectional. I just used a resistor
and two pins on the parallel port for this (output from computer via
resistor, input on ACK pin directly connected), but there are many
approaches you can take.

The protocol for serial programming isn't complicated, and is fully
documented in a dedicated datasheet on Microchip's website.

Gillette - the best a man can forget