Byron A Jeff wrote:

> BTW I think that USB to serial is a better investment.

It's not just a better investment, it's an absolutely neccessary one. If
you do any tech at all, you need a serial port.

I've done PIC development three different ways:

1. True hardware emulator

2. ICD/ICD2

3. Serial bootloader

#1 and #2 suffer from power cycling issues. Unless your circuit draws very
little current, you end up haveing to mouseclick and flip switch in just
the right order or everything hangs.

#1 is very expensive.

#1 is very noisy if you are doing analog stuff.

#2 uses pins you really want to use for other things.

#2 gives you very little in the way of debugging.

#1 and #2 are most useful when you can single step. Not useful at all in a
realtime circuit, especially one that can self-destruct if stopped at the
wrong time.

#3 uses just one cable, no extra power, is fast, and you can debug through
it. Sure you have to include a serial output routine in your code to do
it, but it doesn't take much to set up the usart and output a byte where
you'd put a breakpoint.

So in the future, you'll have a serial port or it'll be on your list
anyway. Getting a bootloader into the PIC is the important thing. Byron's
circuit with 555's is a step in the right direction. You can still get
them at Radio Shack! And the circuit could also be built with schmitt
triggers or oneshots if you prefer.

Cheerful regards,

Bob


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