Re: VIA shift register "bug"

From: A. Fachat <afachat_at_gmx.de>
Date: Sat, 3 Feb 2024 17:25:36 +0100
Message-ID: <fb446ef4-5da5-4527-9943-16b9b6942344_at_gmx.de>
Am 03.02.24 um 17:16 schrieb A. Fachat:
>
> Am 03.02.24 um 17:08 schrieb Robert Di Benedetto:
>> Dumb question but - if WDC revs the mask and adds asynchronous
>> support, does this mean that simply replacing the VIA's in the stock
>> C64 and 1541 gets us faster I/O?  Or is additional modification needed?
>
>
> No.
>
> 1st. The CIA cannot be replaced with a VIA, they are too different.
>
> 2nd. Certain wires are missing on the boards
>
> 3rd. you'd need to add support for the fast protocol into the ROMs.
>
>>
>> -----Original Message-----
>> From: A. Fachat <afachat_at_gmx.de>
>> Sent: Saturday, February 3, 2024 5:30 AM
>> To: cbm-hackers_at_musoftware.de
>> Subject: VIA shift register "bug"
>>
>> Hallo all,
>>
>>
>> in case you haven't noticed, I have investigated the VIA shift
>> register bug together with Dave McMurtrie and Martin Thierer, and got
>> some news from WDC about it - all published in my latest two YT
>> videos (still have to write it up...)
>>
>>
>> The VIA shift register bug: https://youtu.be/6cwVQahVCdc
>>
>> The VIA followup: https://youtu.be/nvnz_34uWSg
>>
>>
>> Oh, btw. I implemented the Commodore Fast Serial bus with a VIA shift
>> register as well. Code is here
>> https://github.com/fachat/via-sr-bugtest/blob/main/fiec/upet-fiec-core.a65
>>
>>
>>
>> Best regards,
>>
>> André
>>
>>
Received on 2024-02-03 18:00:19

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