From 994b3b39f77c0dad176e521eea480bac506b8232 Mon Sep 17 00:00:00 2001 From: AJR Date: Sat, 20 Oct 2018 00:14:22 -0400 Subject: x2201: More notes (nw) --- src/devices/machine/x2201.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/devices/machine/x2201.cpp b/src/devices/machine/x2201.cpp index eb7ebd50f05..ec252d1b8dd 100644 --- a/src/devices/machine/x2201.cpp +++ b/src/devices/machine/x2201.cpp @@ -8,13 +8,18 @@ an EĀ²PROM overlay. Besides having separate data input and output lines (and only one of each), its interface differs slightly from the later NOVRAMs in requiring an active chip select during recall - and store operations. + and store operations. The CS and STORE lines, however, may be + deactivated before the operation completes (in 2 to 4 ms). While US patent 4535411A suggests that this device was sometimes used in groups of eight to simulate a byte-wide memory, the emulation (for the most part) assumes each bit will be accessed separately and packs them into bytes for storage efficiency. + X2202 has the same internal organization and data addressing as + X2201, but its recall operation works on individual bits instead + of the entire array. + **********************************************************************/ #include "emu.h" -- cgit v1.2.3