Re: How do I add firmware to a card?

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

Alex Freed wrote:
> "Tristan Mumford" <xtristan.xmumford@xgmail.xcom> wrote in message
> news:45a07cb2$0$38175$c30e37c6@lon-reader.news.telstra.net...
> >
> > The uC is attached directly to the apple bus via it's PSP and a few extra
> > lines like a couple of address lines maybe?
> >
>
> Gentlemen, before you get carried away please try to model the timing with a
> simulator
> or even on a piece of paper.

Agreed. I was envisaging using a bidirectional register to capture the
data bus, and an additional register to capture R/W, and the 4 address
lines during DEVSEL, then provide these to the uC when DEVSEL goes
high.

Since a command would have to be issued to the uC before a read occurs,
it's therefore unnecessary to meet the timing requirements of the 6502
access cycle.

How did you solve the issue in your design, logic wise?

Matt