On Mon, Feb 06, 2006 at 06:11:45PM +0100, Tomas Larsson wrote:
> You are  forgetting one very important thing, todays PC (and yesterdays PC
> as well) are simply not designed for this purpose, they are designed to use
> peripheral equipment, such as programmer HW to communicate on the lower
> level.

I don't think that's true. USB was developed to give a single port with
hot plug, hardware autodetect, and reasonable speed. This takes some
complexity to accomplish. I get that. But its surge is going to wipe
out other modes of interfacing.

> There will never be a good way of controll serial ports, lpt or USB
> ports, simply because they are not designed for that purpose.

Serial and parallel port control interfaces have been defined for 20
years. One can take a 1985 DOS program and still wiggle the serial and
parallel ports with it. It's a de facto standard... One unfortunately
that is going extinct.

> 
> A PC based on x86 can't do realtime controll, why, because all IO is
> DMA-based, it simply takes to much time to flush the cashe and reload it.
> Therefore you are better of having some dedicated HW that does the actual
> controll and timing.

No argument there.

> Once you have an working bootloader and a standard port (RS232, USB....) on
> your target then you could use anything to communicate and download what you
> want, but to get there you need some dedicated HW-Tools.

I disagree here. It's the crux of the discussion. With some compromises
(USB to serial cable, 3 wire interface only) and some simple tools, it is
possible to gain enough control to bootstrap the rest. No dedicated tools
required.

> I simply can't understand the problem, konnect the programmer, start upp the
> SW download and verify your code, cant be simpler, and not very expensive
> either. Me myself, I'm using the PicKey from FED, which is a marvelous piece
> of equipment.

A lot of hobby PIC development was fueled by the fact that one could
build one's own development tools. Why should that ability disappear
simply because the ports that supported it disappears?

BAJ
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