Re: Differences between 8501R1 and 8501R4

From: Frank Wolf <webmaster_at_frank-wolf.org>
Date: Thu, 5 Dec 2019 14:22:27 +0100
Message-ID: <03c0027d-9107-08b3-ab4d-bc4dfdb50abe_at_frank-wolf.org>
On 05/12/2019 14:13, Gerrit Heitsch wrote:
>
>> The 8501 still contains some left overs of the SYNC at the top where 
>> the bias generator
>> now resides. Therefore I guess that it came first or at the same time 
>> as the 8500
>> jsut has some wires removed or cut (compared to the 8501).
>
> Not quite.. Bit 5 of the I/O-Port does not exist on the 8501 die while 
> the 6510 and 8500 contain a full 8Bit port, you can set and read all 8 
> Bits on them (*). So there must have been a few  more changes between 
> 8501 and 8500.
>
No. Look at the dies yourself -> No other changes - except the ones 
mentioned and the missing port bit.

I still hold to my assumption that the masks for the 8500 were derived 
from the 8500 masks.
Received on 2020-05-29 23:44:38

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