Hi,
> Looking inside the CX5M, I noticed that it has a rather curious
> arrangement of DRAM. There are 8 4116 chips for the 16K of VRAM attached
> to the TMS video chip and 4 41416 chips for the 32K of main memory. This
> is curious because these are two different 16K technologies, one 1 bit
> wide and the other 4 bits. Why use both in a design? Surely 6 41416 chips
> would have been cheaper?
Maybe cheaper or not, but I think that it has something to do with the
VRAM speed etc. needs. Also SVI-738 has originally same 1 bit and 4 bit
configuration...
> Perhaps it has something to do with refreshing. Maybe the TMS can't
> refresh 8 row addresses that the 41416s require, whereas the main circuit
> can. In that case, it ought to be quite easy to replace those 16K x 4
> DRAMs with some 41464 64K x 4 chips, and play around with the slot select
> signals a bit to get 128K in the CX5M. Has this been done before and been
> documented somewhere on the net?
Actually something like this has been done already, but that was done
by Yamaha. There was 128Kb main RAM version from CX5M if I remember
correctly (check faq).
Greetings: Saku Taipale, [EMAIL PROTECTED]
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