NEO-MGA: Difference between revisions

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Multi-purpose chip found in CD systems and some late MVS boards:
Multi-purpose chip found in CD systems and some late MVS boards:
* NEO-MGA in the CD1 model (front loading).
* NEO-MGA in the CD1 model (front loading).
* {{Chipname|NEO-MGA-T}} in the CD2 model (top loading) and {{PCB|MV1A}} MVS boards. Probably the same but made by Toshiba.
* {{Chipname|NEO-MGA-T}} in the CD2 model (top loading) and {{PCB|MV1A}} MVS boards, can be swapped with NEO-MGA.
* {{Chipname|NEO-MGA-T2}} in the [[CDZ]], probably the exact same chip made with a different pinout or manufacturing process.
* {{Chipname|NEO-MGA2-SA}} in the [[CDZ]], replaces the {{Chipname|LC8953}} ?


It is used for address decoding, communication with the [[CD drive]], for refreshing {{Chipname|68k}} [[DRAM]], and for buffering serial [[CDDA]] data.
It is used for address decoding, communication with the [[CD drive]], for refreshing {{Chipname|68k}} [[DRAM]], and for buffering serial [[CDDA]] data.


=CD pinout=
=CD pinout=
Pin 93: GND !


[[File:Neo-mga_CD_pinout.png|700px]]
[[File:Neo-mga_CD_pinout.png|700px]]

Latest revision as of 23:22, 20 September 2022

File:Cd1 neo-mga.jpg
Package QFP160
Manufacturer
First use 1994 ?
Used on CDROM-2 board, MV1A...

Multi-purpose chip found in CD systems and some late MVS boards:

  • NEO-MGA in the CD1 model (front loading).
  • NEO-MGA-T in the CD2 model (top loading) and MV1A MVS boards, can be swapped with NEO-MGA.
  • NEO-MGA2-SA in the CDZ, replaces the LC8953 ?

It is used for address decoding, communication with the CD drive, for refreshing 68k DRAM, and for buffering serial CDDA data.

CD pinout

Pin 93: GND !

File:Neo-mga cd.odg

MV1A pinout

File:Neo-mga mv1a.odg

Signals

  • DRM*, RAS, CAS, WRITE: See TC514400 DRAM datasheet.
  • X*: See LC8953 datasheet.