[sdiy] transistion from 7489/74189 to more modern ram??

[Rainer Buchty]

On Sat, 17 Dec 2011, dan snazelle wrote:

> I have looked through the Jameco Rams and they seem to all have a 
> shared DATA in/out can anyone recommend some (pretty easy) to get 
> SRAMS that have seperate data ins and outs? capacity is not an issue.

How about using 2x 74244/245 with the RAMs of you need shared buses?

One's enable goes to /CS*WR (-> read enable, creates RAM>74245>data out),
the other's to /CS*/WR (-> write enable, creates data in>74245>RAM).

Along the lines of replacing 74(1)89, I wonder if it isn't just way 
cheaper to create a little VHDL design which abuses an FPGA's BlockRAM 
and SelectRAM -- forming the desired amount of 74(1)89 lookalikes 
-- together with some level shifters. (Or, in worst case, go for 
something like M4A-64/32 as single-chip replacement.)

Rainer