| How does the Language Card let other cards handle D000-FFFF accesses? [message #368137] |
Thu, 24 May 2018 13:28  |
zellyn
Messages: 173
Registered: April 2013
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The Language Card *also* replaces the ROM in the Apple II or II+. Which means it's serving up D000-FFFF all the time - either RAM or ROM.
I was wondering how it manages to have D000-FFFF always active, but also not step on other cards that wish to serve up D000-FFFF.
Zellyn
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| Re: How does the Language Card let other cards handle D000-FFFF accesses? [message #368139 is a reply to message #368137] |
Thu, 24 May 2018 14:15  |
Patrick Schaefer
Messages: 67
Registered: October 2012
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Am 24.05.2018 19:28 schrieb Zellyn:
> I was wondering how it manages to have D000-FFFF always active, but
> also not step on other cards that wish to serve up D000-FFFF.
It does not. Both the Language card (with ROM chip) and the Microsoft
16k card drive /INH but do not react to it. That means any other device
thats wants to replace onboard ROM has to switch off the Language Card
first.
The Wildcard puts $C081 onto the address bus when the pushbutton is
pressed. This turns off the LC before enabling its own ROM.
Patrick
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| Re: How does the Language Card let other cards handle D000-FFFF accesses? [message #368144 is a reply to message #368139] |
Thu, 24 May 2018 15:14 |
zellyn
Messages: 173
Registered: April 2013
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On Thursday, May 24, 2018 at 2:15:20 PM UTC-4, Patrick Schaefer wrote:
> It does not. Both the Language card (with ROM chip) and the Microsoft
> 16k card drive /INH but do not react to it. That means any other device
> thats wants to replace onboard ROM has to switch off the Language Card
> first.
>
> The Wildcard puts $C081 onto the address bus when the pushbutton is
> pressed. This turns off the LC before enabling its own ROM.
But $C081 only deselects RAM. It still provides the updated ROM though, right? How do you get it to stop doing that?
Zellyn
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| Re: How does the Language Card let other cards handle D000-FFFF accesses? [message #368169 is a reply to message #368166] |
Fri, 25 May 2018 19:46 |
zellyn
Messages: 173
Registered: April 2013
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On Friday, May 25, 2018 at 5:04:37 PM UTC-4, James Davis wrote:
> You should read the:
ftp://public.asimov.net/pub/apple_II/documentation/hardware/ storage/memory/APPLE_Language_Card_Installation_Operation_Ma nual.pdf
That is, in fact, the document I've been looking at. However, I jumped straight to the programming part and memory maps, ignoring the part where you pull an IC out of your motherboard and plug a cable in and Oh lord, this isn't just a normal slot card at all is it now?!
:-)
Thanks,
Zellyn
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| Re: How does the Language Card let other cards handle D000-FFFF accesses? [message #368180 is a reply to message #368169] |
Sat, 26 May 2018 08:11 |
Patrick Schaefer
Messages: 67
Registered: October 2012
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Am 26.05.2018 01:46 schrieb Zellyn:
> That is, in fact, the document I've been looking at. However, I jumped
> straight to the programming part and memory maps, ignoring the part
> where you pull an IC out of your motherboard and plug a cable in and
> Oh lord, this isn't just a normal slot card at all is it now?!
The cable is needed to steal the lower address lines from the mainboard.
So the card does not need its own refresh counter and multiplexers.
Microsoft 16k does the same, Saturn/Titan have their own logic on board.
Patrick
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