> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Bob Blick
> 
>> 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

I've used #1 and #2. I think #1 does help a lot. And I am using
the ICD2 to help my design now. I can not use #3 since the chip 
I used does not support bootloader function. Take note all the 
"standard flash" PICs does not support bootloader. This may
or may not be a limitation for the hobbyists though.

> #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.

Agreed.

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

True. Still the emulator/debugger will mainly help you
with the firmware development, not the analog stuff.
For that you need a good oscilloscope!

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

#3 also uses pins you want to use as well.

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

I think ICD2 is good enough for quite some development.
And there are simulators as well to help out.

> #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.

You do not hook your ICE/ICD2 to that. You can simulate the output
using relays/LEDs/Beepers/... 
 
> #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.

As much as I see your points, I think your give the impression
that #3 is better than #1 and #2. I think that is wrong. If
one can afford an ICE2000/ICE4000 and the processor modules,
by all means go and get it. It will help a lot. An ICD2 is
one of the best investment for PIC development at its money.

Serial based monitor/debugger is good in some cases. However,
an ICD2 and an ICE will be a very useful tool to speed up the
debugging process.

This is similar to software debugging. Yes, "printf"s
(similar to the serial monitor) will help the debugging. 
But a good debugger will also help. People use debug/gdb/...
(similar to ICE/ICD) to help troubleshooting as well.
 
> 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.
> 

Even though I agree to have a bootloader in certain cases is
good, I do not think it is such an important thing and is
not necessary in many cases. For newbies, it complicates the 
developing and debugging process.

Regards,
Xiaofan



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