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Detecting Rev A vs. Rev B Apple //e in software? [message #389462] Wed, 22 January 2020 18:02 Go to next message
Anonymous
Karma:
Originally posted by: Frank M.

Hello All!

Is there a way to detect whether a program is running on a Revision A Apple //e (the version without double-lores and double-hires graphics)?

In Understanding the Apple IIe, there's some info in Appendix G that says that maybe motherboard ROM is disabled if AN3 is active? It seems a little inconclusive. Anyone out there have any ideas about how this could be accomplished?

F
Re: Detecting Rev A vs. Rev B Apple //e in software? [message #389463 is a reply to message #389462] Wed, 22 January 2020 20:35 Go to previous messageGo to next message
Michael J. Mahon is currently offline  Michael J. Mahon
Messages: 1767
Registered: October 2012
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Senior Member
Frank M. <frank_o_rama@hotmail.com> wrote:
>
> Hello All!
>
> Is there a way to detect whether a program is running on a Revision A
> Apple //e (the version without double-lores and double-hires graphics)?
>
> In Understanding the Apple IIe, there's some info in Appendix G that says
> that maybe motherboard ROM is disabled if AN3 is active? It seems a
> little inconclusive. Anyone out there have any ideas about how this could be accomplished?
>
> F
>

My reading is that the ROM disable function that used to exist on the AUX
connector was reassigned to FRCTXT’. Since this function is not
controllable from software, I doubt that software detection of revision
level is possible.

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
Re: Detecting Rev A vs. Rev B Apple //e in software? [message #389465 is a reply to message #389462] Thu, 23 January 2020 10:46 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: fadden

On Wednesday, January 22, 2020 at 3:02:29 PM UTC-8, Frank M. wrote:
> Is there a way to detect whether a program is running on a Revision A Apple //e (the version without double-lores and double-hires graphics)?

Apple II Tech Note Miscellaneous #7 explains how to programmatically identify which Apple II you're running on:

http://www.1000bit.it/support/manuali/apple/technotes/misc/t n.misc.07.html

It shows you how to tell the difference between a //e and an enhanced //e, but does not say anything about Rev A vs. Rev B, suggesting that it's not possible to tell the difference.

According to wikipedia the Rev B update was free, so there may not be many Rev A machines around.
Re: Detecting Rev A vs. Rev B Apple //e in software? [message #389466 is a reply to message #389462] Thu, 23 January 2020 15:17 Go to previous messageGo to next message
Anonymous
Karma:
Originally posted by: Frank M.

One idea I had was that maybe there is a way to lock to VBL and then read the floating bus after setting double-hires mode. Though I'm assuming the data will be the same, just displayed differently. Just a thought.

f
Re: Detecting Rev A vs. Rev B Apple //e in software? [message #389469 is a reply to message #389466] Thu, 23 January 2020 20:47 Go to previous messageGo to next message
Vince Weaver is currently offline  Vince Weaver
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Registered: April 2013
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On 2020-01-23, Frank M. <frank_o_rama@hotmail.com> wrote:
> One idea I had was that maybe there is a way to lock to VBL and then
> read the floating bus after setting double-hires mode. Though I'm
> assuming the data will be the same, just displayed differently. Just a
> thought.

On a IIe with double-hires I think if you set 80STORE/HIRES/PAGE2 (I'm probably
getting this wrong) it will map AUX-HGR-PAGE1 to MAIN-HGR-PAGE2 to make
double-hires a bit easier. I can't imagine that feature would be there
on a system without double-hires (but I could be wrong). If that's the case
you could enable that, write to an address in HGR-PAGE2, then disable
double-hires and see if the value is in main or aux.

Vince
Re: Detecting Rev A vs. Rev B Apple //e in software? [message #389470 is a reply to message #389466] Thu, 23 January 2020 21:41 Go to previous messageGo to next message
Michael J. Mahon is currently offline  Michael J. Mahon
Messages: 1767
Registered: October 2012
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Senior Member
Frank M. <frank_o_rama@hotmail.com> wrote:
> One idea I had was that maybe there is a way to lock to VBL and then read
> the floating bus after setting double-hires mode. Though I'm assuming the
> data will be the same, just displayed differently. Just a thought.
>
> f
>

That approach crossed my mind, but the timing difference is less than one
cycle, so unlikely.

--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
Detecting Rev A vs. Rev B Apple //e in software? [message #389476 is a reply to message #389462] Fri, 24 January 2020 23:38 Go to previous messageGo to next message
gids.rs is currently offline  gids.rs
Messages: 1395
Registered: October 2012
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Senior Member
Why couldn’t one due a test the same way that the RamWorks card is tested for how many banks but using the Page sofswitches C054/C055.

You store a unique byte in main hi-res and a different one in Aux at the same location. When you read them back and the Aux one is the same as Main, then you know it didn’t take
Re: Detecting Rev A vs. Rev B Apple //e in software? [message #389481 is a reply to message #389465] Sat, 25 January 2020 19:05 Go to previous message
Anonymous
Karma:
Originally posted by: R.Kiefer.SPAEM

fadden wrote:

> According to wikipedia the Rev B update was free, so there may not be many
> Rev A machines around.

Really? :-) The Rev.A models were sold just in the USA, AFAIK. I bought
my IIe Rev.A (with a non-international 120V power supply) second hand in
West Germany in 1985. And this one exists today :-)

Regards
Ralf
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