Revision as of 15:59, 16 August 2016

Quintuple 74HC253 4-to-1 multiplexers with common select lines, making 10 switches in one chip.

Only (?) used on second revision 4-slot MVS systems. Not to be confused with the more common NEO-273.

Pinout

OpenOffice Draw file: File:Neo-253.odg

Select signals come from NEO-F0 SLOTA and SLOTB.

@@ Line 2: / Line 2: @@
 Quintuple 74HC253 4-to-1 multiplexers with common select lines, making 10 switches in one chip.
-Only (?) used on second revision 4-slot MVS systems.
-* SLOT4F @ 5E: SDD, PWAIT0, and PWAIT1 mux.
+Only (?) used on second revision 4-slot MVS systems. Not to be confused with the more common {{Chipname|NEO-273}}.
-* SLOT4F @ 5D: ?
-* ...
-== Pinout ==
+=Pinout=
 [[File:Neo-253_pinout.png|512px]]
@@ Line 14: / Line 11: @@
 OpenOffice Draw file: [[File:neo-253.odg]]
-Draft:
+Select signals come from {{Chipname|NEO-F0}} SLOTA and SLOTB.
-,55: selects
+==SLOT4F @ 5E==
-Muxes (0,1,2,3,out):
+*Mux 10~3: SDD7~SDD0
-* 60,61,62,63,59?
+*Mux 2: PWAIT1
-* 49,50,51,52,44?
+*Mux 1: PWAIT0
-* 45,46,47,48,43?
+*Outputs go to CN9
-* 37,38,39,40,41?
-* 33,34,35,36,28?
-* 29,30,31,32,27?
-* 20,21,22,23,24?
-* 12,13,14,15,11?
-* 4,5,6,7,?
-* 64,1,2,3,?
-:sdd7 slot 4,
+==SLOT4F @ 5D==
+==SLOT4F @ 5C==
+==SLOT4F @ 5B==
+==SLOT4F @ 5A==
-:sdd0 slot 4
-:sdd7 slot 3,
-:sdd0 slot 3
-:sdd7 slot 2,
-:sdd7 slot 1,
-/10: ?
-out CN9:59 44 43 41 28 27 24 11
-6 5 4: PWAIT1 4-3-2-1.
-2 1 64: PWAIT0 4-3-2-1.
-? 16? 17? 18? 19? 42? 53?
 [[Category:Chips]]