Re: Strange 8255 behavior

From: groepaz_at_gmx.net
Date: Sun, 10 Jun 2018 16:06:21 +0200
Message-ID: <1778743.KB18ujFeoE@rakete>
Am Sonntag, 10. Juni 2018, 15:55:10 CEST schrieb Segher Boessenkool:
> On Sun, Jun 10, 2018 at 03:39:42PM +0200, groepaz@gmx.net wrote:
> > if its similar as with what ppl did with 6522 and 6526 (i would assume it
> > is) - then expect every dirty trick you can imagine being used by real
> > world software. for example even the subtle differences between the port
> > drivers of port 1 and port 2 are relevant in 6522/26 emulation.
> 
> (Is there any difference on the 6526?)

yes, unfortunately its not documented in detail anywhere (like in the 6522 
datasheet) - but experimentation shows that very likely the port drivers have 
the exact same differences/properties:

the obligatory test program is here:

https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/CIA/ciaports/

> If you call the difference of the drivers of port PA and PB on the 6522
> "subtle"...  That's like "it's just a scratch" I suppose, heh.

:=)

-- 

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<Yago/K2>
Received on 2018-06-10 17:00:05

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