USR quad modems... (ontopic - really!)

17 Aug 2006

...
     It would be
a lot easier to stick 16 of those into a CoCo 3 to get it 
 up to 512K.  
 But the *boards* to stick 'em in aren't exactly easy to find, and Cloud 9 

Err, it's just traces to link the DRAMs to the connectors. And isn't the 
track layout in the service manual (you do have the service manual, 
right?). In which case it would be a lot easier to make your own 
daughterboard than to mess around trying to kludge SRAMs onto the GIME.

There were a lot of myths about how critical the layout was with DRAM 
(and Rainbow printed some of them). Yes, you do need to take care. It is 
a high-speed circuit, you should try to keep traces the same length, 
decoupling is _essential_ as is a low-impedance ground track. But to be 
honest, making an SRAM board that runs at the same speed is no easier.

-tony

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USR quad modems... (ontopic - really!)