Re: Clock Card?

["Bill Garber" <willy46pa@comcast.net>]

"Michael J. Mahon" <mjmahon@aol.com> wrote in message
20030917230428.19477.00001294@mb-m20.aol.com">news:20030917230428.19477.00001294@mb-m20.aol.com...
> Bill Garber wrote:
>
> >I tried ProDOS users.disk and it claims there is no
> >time or date. I tried reading the eprom, however I am not sure
> >if I should read C400 or CC00. They don't display the same
> >info. It is a 2764 which is I believe 8k so I'm not sure how that
> >would read since $100 is all that will fit in the slot memory.
> >How do I find out where the firmware is loading into RAM?
> >You would think just about any clock software would find it.
> >ThunderClock software searches the slots, finds none. NSC
> >looks for it and finds none of course since it isn't looking in a
> >slot at all. ProDOS seems to find nothing. I don't know what to
> >try next.
>
> This clock card (the battery is a dead giveaway) was probably
> produced before the Thunderclock and ProDOS.  (Checking
> chip date codes and/or card copyright date might verify this.)

I'm pretty sure you are right now that I have tried almost
every piece of software for clock cards that I could find.
Where would these date codes be located?

> It has an unusual amount of firmware for a clock card.

One of the cards has a 2764, the other a 2708. The eproms
have the same firmware on them AFAICT without popping
them out and reading with a eprom programmer which I have
coming in a few days. I will investigate further and attempt to
disassemble then.

> Odds are, none of the firmware is loaded into RAM, but
> the ROM is bank-switched into the $C800 space, probably
> by using some of the extra port bits on the 6821.

I'll read from C800 on both cards and see what is there.

> In its "default" state, there is almost certainly slot ROM
> code in the $Csxx space, and a perusal of this code would
> reveal how the 6821 is manipulated.  It probably also uses
> $C800.CFFx space, with the 2KB chunk of ROM mapped
> in depending on the 6821 port settings.

Can you give me exact location codes for say slot 4?

> Try disassembling the $Csxx space and see where it
> leads you.

I will as soon as you verify what location I need to read.

> (BTW, the 5832 requires at least 2.2 volts to keep time, so
> there should be two cells on the card...)

There is only a AA holder on the card, but there is a voltage
boost circuit in place so that is probably correct.

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - willy46pa@comcast.net



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