13 Oct
2007
13 Oct
'07
11:01 p.m.
dwight elvey wrote:
If you use the 4008/9 chips, you can used regular EPROMs and static
RAMs. No need to be upset at not having 4001's or 4002's.
Yes, except for RAM/4002's, see below.
Of course you'll need to memory map your I/O. I
don't recall if the
4008/4009 did I/O separately but it might.
Looking at a schematic of an actual system using all this stuff, the 4008/9 provide:
- ROM: up to 16 pages of 256 bytes (4 binary page select lines, 8 address, 8 data)
- I/O: up to 16 4-bit bi-dir ports (4 binary port select lines, IN/OUT
control lines, 4 data lines)
- RAM: no provision it appears, so you still need a 4002
(or get by with registers, or via I/O)