Re: Attempting to ID an odd C-64 c (?) motherboard

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Wed, 10 Mar 2021 11:38:13 +0100 Message-ID: <a202eaca-912f-a431-4085-bb0bcdb1ab42_at_laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 3/10/21 10:59 AM, Konrad B wrote:
>> My guess is this board was supposed to replace the 250425, but they ran
>> into some kind of problem(s) and had to make the 250466 as a stopgap
>> until the 250469 was ready.
>>
>>    Gerrit
>>
> 
> Looking at the board -  doesn't it have !CAS1 (pin 19 of the gate array)
> connected to DRAMs CAS line ? 251715-01 has these CAS0..CAS3 lines (pins
> 18..21) that are gone in  252535-01, I was always wondering what they could
> be for and if they could be abused...

Someone needs to decap a 251715-01 and find out. :)

And I think in 252535-01 they needed the lines for the 4 data lines of 
the built in color RAM.

  Gerrit