Date   : Mon, 11 Aug 1986 18:57:51 GMT
From   : Fred Bowen <fred%cbmvax.cbm.uucp@BRL.ARPA>
Subject: Re: RAM expansion modules for C128

> Can anyone tell me from where can I obtain the circuit diagram for the 128k
> or 512k versions of the RAM expansion modules for the Commodore 128.

As far as I know, Commodore is has no plans to publish the diagrams.  The RAM
expansion modules consist simply of either 64K x1 or 256K x1 DRAMs and the
8726 (custom) controller.  The controller itself eliminates the need for TTL
address and data buffering.  The controller also provides DRAM refresh.
The C128 (or C64) processor accesses the expansion RAM via instructions to the
controller, which then reads/writes/swaps memory via DMA.  The controller
drives the bus only during phase 2 of the standard 1MHz system clock.
-- 
Fred Bowen                     uucp:   {ihnp4|seismo|caip}!cbmvax!fred
                               arpa:   cbmvax!fred@seismo.CSS.GOV
                               tele:   215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380