MMU

Description

Selects cartridge banks, hw chips, osrom, BASIC rom. In older machines had no Atari number, was PAL16L8.

Catalogue numbers

CO60609 (1200/1400)
CO61618 (XL/XE)
C101686 (XEGS)

Pinout (CO61618)


pinout
/MAP IN from PB7 - low selftest on, hi selftest off
RD4 IN from cartridge port
RD5 IN from cartridge port
REN IN from PB0 - low OS off, hi OS on
/REF IN refresh
/S5 OUT cart bank select
/BASIC OUT basic rom chip select
/MPD IN MPD PBI
/OS OUT OS rom chip select
/CI OUT CAS inhibit
/IO OUT goes to 74LS138, selects hw chips (Y0 - GTIA, Y2 - POKEY, Y3 - PIA, Y5 - CCTL)
/BE IN from PB1 - low BASIC in, hi BASIC out
/S4 OUT cart bank select
Here is PAL (2 KB SRC) source by Bob Woolley and GAL (0 KB SRC) source from Erhard Puetz. I didn't check them for correctness (which means nothing... :) .
Atari pages accessed Counter times. Last modified: Sun Mar 25 23:49:58 2001
(c) 1998-2001 Jindroush
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