NEO-253
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.
- SLOT4F @ 5D: ?
- ...
Pinout
OpenOffice Draw file: File:Neo-253.odg
Draft:
54,55: selects
Muxes (0,1,2,3,out):
- 60,61,62,63,59?
- 49,50,51,52,44?
- 45,46,47,48,43?
- 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,?
63:sdd7 slot 4, 52 48 40 36 32 23 15:sdd0 slot 4
62:sdd7 slot 3, 51 47 39 35 31 22 14:sdd0 slot 3
61:sdd7 slot 2, 50 46 38 34 30 21 13
60:sdd7 slot 1, 49 45 37 33 29 20 12
9/10: ?
out CN9:59 44 43 41 28 27 24 11
7 6 5 4: PWAIT1 4-3-2-1. 3 2 1 64: PWAIT0 4-3-2-1.
8? 16? 17? 18? 19? 42? 53?