NEO-253
Jump to navigation
Jump to search
| |
| Package | QFP64R |
| Manufacturer | 
|
| First use | 1992 ? |
| Used on | SLOT4F |
Quintuple 74HC253 4-to-1 multiplexers with common select lines, making ten 4-to-1 switches in one chip. Used to switch read-only buses. The inputs are named according to the related slot: A is slot #1, B is slot #2...
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
Cartridge wait cycle configuration and Z80 bus.
- Mux 1: PWAIT0
- Mux 2: PWAIT1
- Mux 10~3: SDD7~SDD0
Outputs go to CN9.
SLOT4F @ 5D
Sprites and fix layer graphics.
- Mux 1: CR30
- Mux 2: CR31
- Mux 10~3: FIXD7~FIXD0
SLOT4F @ 5C
Sprite graphics.
- Mux 10~1: CR29~CR20
SLOT4F @ 5B
Sprite graphics.
- Mux 10~1: CR19~CR10
SLOT4F @ 5A
Sprite graphics.
- Mux 10~1: CR9~CR0