Re: 6569 luminances

From: Gerrit Heitsch <>
Date: Tue, 15 May 2012 23:11:16 +0200
Message-ID: <>
On 05/14/2012 07:37 AM, Gerrit Heitsch wrote:

> Like here:
>  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.


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Received on 2012-05-15 22:00:14

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