A Home Built (almost) Panasonic/MKE/CR56x CD-ROM Interface
Author :Gary Tait,VE3VBF
This project is based on info provided by Theo Markettos.
And by the C source code of a Linux driver by Zoltan Vorosbaranyi
Please don't bother me with programming info, or implementation of
a Panasonic CDR56x series drive as a stanalone CD player, as I don't
know any programming details. I suggest you peruse the Linux driver source code.
Also don't bother me for drivers, Panasonic should have them, and
don't bother me about the whereabouts of pre-made interface cards,
or the debugging, as I wouldn't know.
Here is a schematic for the main circuit.
Here is a schematic for the address decoder.
Here is a different schematic for the main circuit.
Here is different schematic for the address decoder.
All ICs are TTL 74LSxx types.
The project I am working on was a discrete component paralell printer
port adapter . The address decoder consists of a 74LS138, and a 74LS10,
and a 74ls367 (2+4 gated inverter).The original addresses were jumper selectable 0x278 and 0x378.
A3 is inverted, now producing 0x270 and 0x370 addresses. It has a 74LS32 to help
produce enable lines (by ORing an output of the '138 with either IOR
or IOW) ,a 74LS245 ,and had a 74LS367 (2+4 gated buffer)
The '367 and '368 each have 4 gates controlled by one address line,
and 2 gates controlled by another. (the chips have identical pinout,except
the 368 output is inverted).
I salvaged a shrouded 40 pin header from some old piece of equipment,
and attached it to the to edge of the adapter card.
- CD-Data 0-7 - through 74LS245 octal Bus
Transciever to db0-7
245 Enabled when low on Base+0 AND [Base+2 OR IOR]
245 Dir- low when [Base+0 OR IOR] AND [Base+1 OR IOR]
- CD-Status 0-3 input through gated quad buffer (I use 1/2 74LS244) to
Enabled when low on when IOR OR Base+1
- CD-Reset IOW OR base+2
- Operation Mode bits 0-1 latched to db0-1 when low on IOW OR Base +3
The chip used is a 74LS175.
- CD-Status/Data Enable - Low when Base+0 (low when
status/info is read from or sent to drive,high otherwise)
- CD-Data enable - Connected to 245 enable
- CD-Read -Connected to 245 dir (low when reading info/status/data from drive)
- CD-Write low when I/O Write OR Base+0
The 138 is enabled when G2A,and G2B are low ,and G1 is high.
G2A is controlled by A7 (x8x)
G2B is controlled by ALE
For 0x370,G1 is controlled by NOT [ NAND [NOT A3] ,A8,A4]. A8 is
inverted for 0x270.
C is controlled by NAND A5,A6,A9
B is controlled by A1
A is controlled by A0
Logic and Parts notes
The OR operations are each carried out by 1/4 of a 74LS32 Quad 2 input OR gate
The AND operations are each carried out by 1/4 of a 74LS08 Quad 2 input AND gate
The NOT operations are each carried out by 1/6 of a 74LS368 2+4 gated invertor, with the gate lines
grounded, leaving a hex invertor. You can use a 74LS04 invertor.
The NAND Operations are each carried out by 1/3 of a 74LS10 Triple 3 input NAND gate
IOR is the I/O read signal (low when I/O read operation)
IOW is the I/O write signal (low when I/O write operation)
Base+x is decoded address line
CD-xxxxx is line on CD bus
Operation Mode appears to be a drive select line. For one drive (as most will use),
you may be able to just ground them.
Most signals are active low.
Pleas read my disclaimer
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