AVR-Chat

In my quest for more RAM on an M128 ...

Of course, sadly, I'm answering my own questions here, but 
nevertheless, a few SRAM chips I've looked at, including the Cypress 
CY7C109B have a guaranteed VOHmin of 2.4 Volts (at -4 mA) but the 
Atmel's VIHmin is 0.6Vcc, or 3.0 Volts, when run at 5.0 Volts. This 
says that, if the data bus is loaded by at least 4.0 mA then the SRAMs 
high bits are not guaranteed to be seen by the processor.

I see a number of boards, that are commercially available, use an M128 
connected to this same part (or similarly spec'd part), so I can only 
assume it does work. But clearly this is not a desirable situation.

Here's an example using the Cypress CY7C1019

   http://www.bdmicro.com/images/mav2re2_vsm.jpg
   http://www.bdmicro.com/images/mav2b_phtv_ann1b.jpg

and using the Samsung KM681000 (VOHmin of 2.4 Volts (at -1 mA!!!)

  http://www.prllc.com/productcart/pc/catalog//128MMC.jpg

Anyone think I'm just over cautious?

Peter.