Re: Strange 8255 behavior

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Sun, 10 Jun 2018 16:15:58 +0200 Message-ID: <7e76d273-f020-82af-8676-2ff45fe57108@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 06/10/2018 04:06 PM, groepaz@gmx.net wrote:
> 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:

A die shot should clear that up... here is one:

http://oms.wmhost.com/misc/MOS_6526A_CIA.jpg

The die says '8521R1', on the outside they were still stamped '6526'.

  Gerrit