Re: [stella] FE, 3F, Bankswitching, and Data lines

Subject: Re: [stella] FE, 3F, Bankswitching, and Data lines
From: "Chris Larkin" <clarkin@xxxxxxxxxxxxx>
Date: Tue, 17 Dec 2002 11:27:59 -0800
That should be all you need

--Chris

----- Original Message -----
From: "Adam Wozniak" <adam@xxxxxxxxxxxxxxxx>
To: <stella@xxxxxxxxxxx>
Sent: Tuesday, December 17, 2002 9:54 AM
Subject: [stella] FE, 3F, Bankswitching, and Data lines


> On Sun, 15 Dec 2002, Dan Boris wrote:
> > This was posted to the list a couple days ago:
> >
> > Not quite. ;-) In FE bankswitching A13 is used to identify the
> > two banks. Since this line isn't brought out of the 6507, the
> > FE bankswitching logic waits for two consecutive accesses to
> > this stack. Only JSR/RTS (and BRK/RTI) can do that. At the second
> > access the high byte of the return address is either pushed onto
> > or pulled from the stack. This is where the bankswitching logic
> > finds out which bank need to be mapped in.
>
> I'm running out of pins on my microcontroller.  I've got all the
> address lines, but do I really need to monitor ALL the data lines?
>
> For FE, watching line D5 during the second access is sufficient?
> i.e. I do not need to worry about D0-4 and D6-7 ?
>
> Also, for 3F bank switching, is watching D0-1 sufficient?
>
> Are there any other schemes where the banking logic needs to watch
> the data lines?
>
> --
> Will code for food.       http://cuddlepuddle.org/~adam/resume.html
>
> adam@xxxxxxxxxxxxxxxx        http://cuddlepuddle.org/~adam/pgp.html
>
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