Re: 6569 luminances

From: MikeS <*dm561_at_torfree.net*> Date: Tue, 15 May 2012 17:44:53 -0400 Message-ID: <D5CA14B9148A4DFE89F73DDDFBCFFEE4@vl420mt> · dm561_at_torfree.net

Maybe try some 6114-120s:

eBay: 7625843489
http://www.twistywristarcade.com/5-ram#/

(both mislabelled BTW)

m

----- Original Message ----- 
From: "Gerrit Heitsch" <gerrit@laosinh.s.bawue.de>
To: <cbm-hackers@musoftware.de>
Sent: Tuesday, May 15, 2012 5:11 PM
Subject: Re: 6569 luminances

> On 05/14/2012 07:37 AM, Gerrit Heitsch wrote:
> 
>>
>> Like here:
>>
>> http://www.ebay.de/itm/290695335618
>>
>>  From what I found via Google, the UL224D is a CMOS-Version of the 2114
>> made by ZMD in the GDR when it still existed.
> 
> Since I wanted to find out, I ordered 5 of them and got them today. The 
> good news, they are 2114 compatible. The bad news is that they are 
> labeled 300ns but must be slower since a 2114-3 does work.
> 
> I can access them from the CPU just fine (read and write), but VIC reads 
> garbage. The only explanation I have is the 74LS373 demultiplexer using 
> RAS which goes LOW about 150ns after PHI0 goes low. If the addresses 
> supplied by VIC are also 150ns or so late, this might explain why the 
> CPU can read the RAM while VIC can't.
> 
> They might work in a VIC-20 though.
> 
>  Gerrit
> 
> 
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