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

[Scott Gravenhorst]

Paul Maddox <yo at VacoLoco.net> wrote:
>Dan,
>
> I've got a bunch of 74219s if you're after some? I'm happy to accept offers.
>
>As for standard SRAM, you really need a CPU... they're all 
>slightly different, but mostly you have a Read/Write pin and an 
>output enable pin. 
>
>to read, you usually bring the R/W pin high, put the address on 
>the bus, the enable the "output enable" by bring it low and read 
>the data out. 
>
>To write, ensure output enable is high (disabled), put address 
>onto bus, put your data onto the data bus, and bring the R/W pin 
>low for short period. 
>
>Best guide is a datasheet to be honest, I've got a stack of older 
>DIL SRAMs if you want (16K and 64K IIRC). 

+1 for microprocessor.

In fact often you wind up being able to stuff all the logic into a microprocessor and eliminate
other ICs making the project simpler (construction-wise), less expensive and smaller.  Of course,
that does mean there is a necessity to learn how to program the microprocessor.  And if the RAM
size you need is small enough, you may be able to use the SRAM that is embedded in most modern
microprocessors instead of interfacing an external RAM IC.



-- ScottG
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-- Scott Gravenhorst
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