EPROM emulators (was Re: newbie building a scratch-built computer)

Holger Veit holger.veit at iais.fraunhofer.de
Thu Aug 30 02:32:41 CDT 2007


Dave Dunfield schrieb:
> Btw, for an ultra-simple EPROM emulator, use one of the
> Dallas NVRAM chips (DS1225 (8K) , DS1235 (32K) etc.).
> Stuff it in a RAM socket of a convienent SBC to program
> it, and make an adapter by piggybacking a couple of sockets
> and moving the necessary address lines, mask write etc.
> to plug it into a ROM socket.
>   
Alternative to that is the use of TIMEKEEPER (48Txx) or ZEROPOWER RAMs 
(48Zxx)
which are rather expensive when you hunt for them in the obvious places, 
but I got lots of them
from old Sun IPC/IPX machines before they were thrown out here. Capacity
is typically 2Kx8 or 8Kx8 for these devices, newer ones also have 32K or 
128K.
The timekeeper versions also provide a hardware clock which is useful 
once in a while.

Regards
-- 
Holger




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