Re: Help with SX64 User Port?

Date: Thu, 22 Jun 2017 19:36:06 +0200
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> On 2015-10-13, at 07:48, Gerrit Heitsch <> wrote:
> At the end of 1986, Commodore changed the process from NMOS to HMOS-II. For a short while, some CIAs were labeled '8521R0' but then they went back to the '6526' label. Usually they were also fast enough for get the 'A' for 2 MHz operation. The HMOS-II-CIA also changed a bit timingwise, that's where the legend originated that the 6526A behaves differently than the 6526.

They DO behave differently. For example my old test cart shows CIA related failure when using the "6526A". Do we know how exactly the differ timing-wise? I guess this is related to what Marko wrote yesterday?

SD! -

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Received on 2017-06-22 18:00:05

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