[Coco] 256K RAM chips

[jdaggett at gate.net]

On 24 Dec 2008 at 23:06, Roger Taylor wrote:


> So you're saying the CoCo could use these chips as-is plus they 

> retain their memory when the power is off?


No. It ust means that you do not have to supply refresh (row) addresses  
every 16mS. 

To work on the Coco1/2 you need toset the appropriate SAM bits and then 
demultiplex the Z-Buss to get the full address. The GIME chip and the SAM 
chip outputs the memory address in the form of row and column through 
the Z-Buss. The DRAM chips demux the address to gain the actual 
memory location. 

james