DEC M8350 - KA8E posibus interface

[Vintage Computer Festival]

On Wed, 22 Jun 2005, Joe R. wrote:

> At 11:58 PM 6/21/05 +0100, you wrote:
> >> Also... does anyone know about the differences between 4116 and 4164
> >> chips enough to answer the question if one could use 4164s as long as
> >> one a) prevents the non-TTL supplies from reaching the chips (modify
> >
> >What you need to do is isolate pins 1 and 8 from the board and reconnect
> >pin 8 to +5V IIRC
> >
> >   4116   4164
> >1   -5V    N/C
> >8  +12V    +5V
> >9  +5V     A7
> >
> >That leaves the extra address line tied high, so you only use 1/4 of the chip
> >
> >> board, modify sockets, modify pins...) and b) possibly tie up or tie
> >> down the extra multiplexed address input.  Can you refresh 1/4 of a
> >> 4164 and have just that part stay refreshed?  I ask because I have a
> >
> >There were 2 types of 64K DRAM. One of them used 7 bit refresh (same as
> >the 4116, on the same pins), the other, older/rarer one need all 8
> >address lines to be used for the refresh (this was a royal pain on
> >Z80-based machines, where the CPU provides a 7 bit refresh only).
>
>
> Tony,
>
>    This is good info. Someone should post it as a mini-FAQ.
>
>   Do you have any info on which ones used 7 bit refresh and which ones used
> 8 bit refresh?

I've been taking useful messages and posting them to the FAQ myself,
attributing them to the original message author.  I don't think Tony has
time to reply to messages and then go over to the KB to post them as well.
He has too much hacking to do.

So it's up to you to post them to the KB if you think they are worthwhile.

-- 

Sellam Ismail                                        Vintage Computer Festival
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International Man of Intrigue and Danger                http://www.vintage.org

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