DEC M8350 - KA8E posibus interface

[Gooijen, Henk]

  Ethan,
I can remember (several years ago) my first 6809 kit (bus-based)
that had a 512x256 pixel-addressable graphics option. That Euro board
was TTL and one littlr PROM for RAS/CAS generation. Originally it had
4116 on them, but 3 power voltages with requirements in the order how
they came up (and went away) from the 4116's made me change the 4116
into 4164's. 3-quarter of all the 4164's is not used, but they are
single +5V. Works perfect, but I can't remember what I did with the
two old 4116 power supply pins. AFAIK is is obvious when you compare
the pin of both, at least it was t me at that time.
Ah yes, there was also one extra "address" pin, IIRC. Tie that to GND
or +5, or put a switch (or software controlled output pin to it)
There is your basic "bank-switching"!

  success,
- Henk, PA8PDP.


> Also... does anyone know about the differences between 4116 and 4164
> chips enough to answer the question if one could use 4164s as long as
> one a) prevents the non-TTL supplies from reaching the chips (modify
> board, modify sockets, modify pins...) and b) possibly tie up or tie
> down the extra multiplexed address input.  Can you refresh 1/4 of a
> 4164 and have just that part stay refreshed?  I ask because I have a
> serious wad of new 4164s from COMBOARD stock, but 128Kw of 4116s
> (8 x 12)  is more than I have lying around.

> -ethan