OT Troubleshooting: Old computers with modern parts

[woodelf]

Eric Smith wrote:

>Ramtron ferroelectric RAM (nonvolatile) is available from Newark
>Electronics.  The traditional problem with FRAM is that it had limited
>read endurance, as well as limited write endurance.  Just reading the
>part would wear it out.  The newest 3V parts have fixed that.
>
>The FM18L08 is a 32K*8 3V 70ns part with unlimited endurance.  IIRC,
>the last time I bought some from Newark I paid under $10 each.
>
>  
>
But is that DIP packaging? I got the data sheet but interfacing to 5v 
logic and power
up is where I have lack of knowlage.  I still think  a generic  FRAM  
board needs
to be made  with  3V parts to replace CORE memory in  older machines 
but  I have
no idea how to interface 3V logic with 5 volt logic NOT using  CMOS  parts.

>There is a newer 128K*8 55ns part, the FM20L08.  Newark doesn't have
>it yet.  All American Direct gives a price of $25.59, but it is not
>clear whether they actually have parts in stock.
>
>  
>
I still am dealing with classic small machines ... 2 FM18L08's replace a 
whole rack of
core memory for a PDP/8.   @ 2 cents a bit that is $8K for 8 banks of 4K 
word memory
or $500 1980? $ for 4K.


>If you want to use these in a 5V system, it's probably a good idea
>to use some 74LVC buffers that can function as level translators.
>
>  
>
SMT I think.

>Eric
>  
>
Looking at orginal PDP / 8 ( 1965) prices $800 for a paper tape 
punch/reader today is
a  great deal. $15,000 would buy you a home back then.
Ben