NEO-253: Difference between revisions

From NeoGeo Development Wiki
Jump to navigation Jump to search
mNo edit summary
mNo edit summary
Line 2: Line 2:


Quintuple 74HC253 4-to-1 multiplexers with common select lines, making 10 switches in one chip.
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]]
[[File:Neo-253_pinout.png|512px]]
Line 14: Line 11:
OpenOffice Draw file: [[File:neo-253.odg]]
OpenOffice Draw file: [[File:neo-253.odg]]


Draft:
Select signals come from {{Chipname|NEO-F0}} SLOTA and SLOTB.


54,55: 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,?


63:sdd7 slot 4,
==SLOT4F @ 5D==
52
==SLOT4F @ 5C==
48
==SLOT4F @ 5B==
40
==SLOT4F @ 5A==
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?


[[Category:Chips]]
[[Category:Chips]]

Revision as of 15:59, 16 August 2016

NEO-253 chip found on a SLOT4F board.

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.

SLOT4F @ 5E

  • Mux 10~3: SDD7~SDD0
  • Mux 2: PWAIT1
  • Mux 1: PWAIT0
  • Outputs go to CN9

SLOT4F @ 5D

SLOT4F @ 5C

SLOT4F @ 5B

SLOT4F @ 5A