Re: Carte Blanche

[mdj <mdj.mdj@gmail.com>]

On Apr 3, 8:38 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> Alex Freed wrote:
> > Michael J. Mahon wrote:
>
> >> Steve, it wasn't immediately apparent whether it was possible to
> >> re-program the board while it is installed by running Apple II software.
>
> >> This would enable it to be a real "chameleon card", since configurations
> >> could be loaded into the card in a few seconds to alter its personality.
>
> > This ideas has been discussed on this forum but proved to be a huge
> > task. More on the software side than the hardware side. Porting the
> > JTAG programming tool to an 8 bit CPU with rather limited resources
> > is far from trivial. And if you absolutely have to have it, you
> > probably can. It's not too hard to make a Wiggler-style interface
> > between an Apple parallel card and the JTAG port on Carte Blanche. Just
> > write the software :)
>
> I'd be glad to write the software if it comes to that.
>
> But I'd rather access the card through its bus connection than by
> using another (parallel) card.  Since an Apple parallel card is
> little more than an 8-bit latch, that doesn't seem difficult.
>
> I presume that the data formats and protocols for JTAG programming
> are straightforward...  I'd expect what is essentially a "copy file
> to port" operation, with some handshaking, initialization, and cleanup.

The main complexity is not in the JTAG protocol implementation but
rather the programming protocol that overlays it.

Matt