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echo: apple
to: comp.sys.apple2
from: Michael J. Mahon
date: 2009-02-17 19:01:04
subject: Re: More fun with Freed Z80

a2retro wrote:
>  To: a2retro
> a2retro wrote:
> 
>> alex.freed.007 wrote:
>>
>>> The 128K version is particularly easy to use with a battery back-up as
>>> it has an active high second chip select. Most likely just adding a 
>>
>>  > diode and a coin cell will make it NV.
>>
>> I have seen this implemented on a few other projects. zxmmc+ for example.
>>
>> I plan to use this approach for my //cmxp project.
>>
>> Cypress also has an interesting part CY14B104L-ZS45XC - combo 
>> SRAM/Flash with autosave.
>>
>> Glenn
> 
> 
> For anyone updating their card to a 512K ram - double check the 
> datasheet from your vendor of choice, as I see there doesn't seem to be 
> a standard on pin A17 and A18. They are interchanged across vendors.

Who cares what they label the address pins on a static RAM?
It's just address bits in --> data out.

-michael

NadaNet and AppleCrate II: parallel computing for Apple II computers!
Home page: http://home.comcast.net/~mjmahon

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