Latest revision as of 23:22, 20 September 2022

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 !

@@ Line 8: / Line 8: @@
 }}
-NEO-MGA is a custom chip apparently noone knows about, which is found in 3 versions 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).
-* {{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 with a different pinout and maybe stuff related to the [[copy protection]] system.
+* {{Chipname|NEO-MGA2-SA}} in the [[CDZ]], replaces the {{Chipname|LC8953}} ?
-It is used for communication between the main board and the [[CD drive]], for handling [[DRAM]] access (?), address decoding (?) and for buffering [[CDDA]] data.
+It is used for address decoding, communication with the [[CD drive]], for refreshing {{Chipname|68k}} [[DRAM]], and for buffering serial [[CDDA]] data.
-=Pinout=
+=CD pinout=
-[[File:Neo-mga.png]]
+Pin 93: GND !
-,10,15,16,18,30,41,50,59,70,81,90,110,121,130,139,150: Ground.
+[[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]]