Revision as of 07:34, 11 May 2018

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. Probably the same but made by Toshiba.
NEO-MGA-T2 in the CDZ, probably the exact same chip made with a different pinout or manufacturing process.

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

CD pinout

@@ Line 1: / Line 1: @@
-[[File:cd2_mga.jpg|right|thumb|NEO-MGA-T chip found on a CDM3-2 board.]]
+{{ChipInfo
+|picture=cd1_neo-mga.jpg
+|pkg=QFP160
+|manu=fujitsu
+|date=1994 ?
+|gates=?
+|used_on={{PCB|CDROM-2 board|CDROM-2}}, {{PCB|MV1A}}...
+}}
-The NEO-MGA-T is a damn chip nobody knows about, which is found in the CD1 and CD2 versions of the NeoGeo hardware.
+Multi-purpose chip found in CD systems and some late MVS boards:
-The CD-Z has a NEO-MGA-T2, probably to handle the faster CD reading speeds and new copy protection system.
+* NEO-MGA in the CD1 model (front loading).
-The front loading NeoGeo CD has a NEO-MGA chip.
+* {{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-T2}} in the [[CDZ]], probably the exact same chip made with a different pinout or manufacturing process.
-It's in charge of the communication with the CD drive, data transfers to the [[LC89515]] host and buffering CDDA data for the [[BIOSes]] vu-meters.
+It is used for address decoding, communication with the [[CD drive]], for refreshing {{Chipname|68k}} [[DRAM]], and for buffering serial [[CDDA]] data.
-[[Catégorie:Chips]]
+=CD pinout=
+[[File:Neo-mga_CD_pinout.png|700px]]
+[[File:Neo-mga_cd.odg]]
+=MV1A pinout=
+[[File:Neo-mga_MV1A_pinout.png|700px]]
+[[File:Neo-mga_mv1a.odg]]
+=Signals=
+* DRM*, RAS, CAS, WRITE: See TC514400 DRAM datasheet.
+* X*: See [[LC8953]] datasheet.
+[[Category:Chips]]