Super Disc Expansion Drive
This drive uses the EXT port for communication (while not directly plugged). Because this uses the B-Bus Memory, it can only use $21xx registers.
$21D0 - ? (Always zeroes it)
$21E0 - ?
$21E1 - NEC D75P308GF Interface
$21E2 - Sony CXD1800Q Register Select
$21E3 - Sony CXD1800Q Interface
$21E4 - Interrupt Enable
d1 = ?
d2 = Sony CXD1800Q (Decoder)
d3 = NEC D75P308GF (Mecha)
$21E5 - ?
NEC D75P308GF Interface
Status
0x0X - Nibble Receive
0x80 - Ready Flag
Commands
Nibbles (a hex digit here) are sent back and forth:
At every nibble you send, a nibble should be read when the Ready flag is set. An interrupt seems to be sent when the ready flag is set.
Command | Serve (Hex) | Receive (Hex)
----------------------------------------------------------------------
ACCESS TRACK/INDEX | CttiiF | FFFFFF
ACCESS MM/SS/FF | BmmssffF | FFFFFFFF
STOP | D01F | FFFF
PLAY | D02F | FFFF
PAUSE | D03F | FFFF
OPEN / CLOSE | D04F | FFFF
FAST FORWARD | D10F | FFFF
FAST REVERSE | D11F | FFFF
FORWARD | D12F | FFFF
REVERSE | D13F | FFFF
KEY DIRECT | D40F | FFFF
KEY IGNORE | D41F | FFFF
CONTINUOUS PLAY | D42F | FFFF
AUTO TRACK PAUSE | D43F | FFFF
AUTO INDEX PAUSE | D44F | FFFF
NORMAL SPEED | D45F | FFFF
DOUBLE SPEED | D46F | FFFF
Q-DATA REQUEST | D50F 0000000000000000F | FFFF ................F
STATUS REQUEST | D51F 01234F | FFFF .....F
RESTORE | F | F
Q-Data Request
TODO
Status Request
TODO
Sony CXD1800Q Interface
Write Selection to $21E2
, then write/read byte by byte to/from $21E3
.
Seems to be similar to CXD1196AR (which the datasheet could be found).
Selection - Size - Name
[WRITE MODE]
X1 - 8-bit - DRIF
X2 - 8-bit - CHCT
X3 - 8-bit - DECT
X4 - 8-bit - INMS
X5 - 8-bit - INCL
X6 - 8-bit - CI
X7 - 16-bit - DMAD
X9 - 16-bit - DMXF
XB - 16-bit - DRAD
0D - 8-bit - PLBA
[READ MODE]
00 - 8-bit - DMA
01 - 8-bit - INST
02 - 8-bit - STS
03 - 8-bit - HFLG
X4 - 8-bit - HMIN
X5 - 8-bit - HSEC
X6 - 8-bit - HBLK
X7 - 8-bit - HMOD
08 - 8-bit - SFIL
09 - 8-bit - SCH
0A - 8-bit - SMOD
0B - 8-bit - SCI
0C - 16-bit - CMAD
XE - 8-bit - MDFM
XF - 8-bit - ADPC
18 - 16-bit - DMXF
1A - 16-bit - DMAD
1C - 16-bit - DRAD