Lots of information is not known at this time.
It uses ports fbe0-fbe3. The exact decoding and operation of these ports is unknown.
fbe0 This port is read only it seems. bits 7..4 seem to be related to the dip switches on the CSD with bit 7 seems to be fixed to GND/0v.
bit 6,5 is the timer value. It is the time allowed between choosing next cartridge to play.
bit 6, bit 5
off off = 8 1 1
off on = 16 1 0
on off = 24 0 1
on on = 32 0 0
bit 4 seems to be timer on/off for time limited play.
fbe0 bits 3..0 are defined by the dial
bit 3 is ignored.
bit 6, bit 5
off off = 8s 1 1
off on = 16s 1 0
on off = 24s 0 1
on on = 32s 0 0
bit 4 seems to be timer on/off for time limited play.
bits 3..0 are defined by the dial
bit 3 is ignored.
0 = forever?
1 = 8s,
2 = 56s
fbe2 is read only it seems
bits 7..3 are the currently selected cartridge
bits 3..0 ???
fbe1 is writeable
bits 7,6: ???
bits 5..0: are cartridge number??
fbe3 is writeable:
bits 7..4: are cartridge number
bits 3..0: ???
fbe2 is read only it seemsbits 7..3 are the currently selected cartridgebits 3..0 ???== The CSD System Cartridge ==
The system cartridge uses the following plus features:
* sprites
* palette
* raster interrupts
fbe1 The software reads each of the 12 slots to determine if there is writeable bits 7,6: ???bits 5a cartridge installed..0It also looks for a specific header which can be recreated with the following code: are cartridge number??
fbe3 is writeable org &0000 start:bits 7 ;; a standard cartridge is executed here when inserted into ;; a CPC+..4 jp start1 ;; a JP instruction at &0000 defb "AMS" ;; this is the important identification jp start2 ;; a JP instruction at &0006 jp start3 ;; a JP instruction at &0009 start1: are cartridge numberbits 3 ld bc,&7f00 out (c),c ld bc,&7f4f out (c),c jp start1 start2: ld bc,&7f00 out (c),c ld bc,&7f4b out (c),c jp start2 start3: ld bc,&7f00 out (c),c ld bc,&7f40 out (c),c jp start3 end start Offset 0 is the normal execution point for cartridges when run on GX4000 and Plus. It is believed the others are for a rolling demonstration mode, and a play mode that is limited. The only cartridge to have this header is [[Pang (cartridge)|Pang]].0: ???
== Pictures ==
Image:csddaughter.jpg
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== Download ==
* [[Media:CSD Jukebox.cpr]] (JukeBox Cartridge .CPR file)
Courtesy of Amstrad.cpc.free.fr
[[Category:Hardware]][[Category:CPC Plus]][[Category:Amstrad Products]][[Category:Cartridges]][[Category:Expansion ROM]]