The CDK-006 uses a proprietary control interface using TTL-level signals on a DC37 connector:
|1-4||ECMD3..0||in||command from controller|
|5||L/R*||in||local or remote control|
|6||HELP*||out||indicates changer in test mode|
|7||CHECK||out||indicates power up|
|18||EXAM*||in||SIRCS (IR remote control) input|
|20||CLOSE||out||magazine present and door closed|
|21||EACK*||out||command handshake, indicates command nibble accepted|
|22||EREQ*||in||command handshake, indicates command nibble available|
The changer has a four-bit parallel input port (from its point of view), ECMD3..ECMD0. The controller drives the L/R* signal low to indicate that it wants to talk to the changer. As the controller presents each nibble of the command, it asserts the EREQ* line, waits for the changer to assert the EACK* line, deasserts thte EREQ* line, and waits for the changer to deassert EACK*. After the entire command has been handshaked out in this manner, the controller raises L/R*.
The changer provides command result and status codes to the controller on a four-bit output port, QDATA3..QDATA0. There is a strobe line QSTB* which signals valid data. Since there isn't two-way handshaking on the status, the controller has to accept each status nibble within 230 uS of the falling edge of QSTB*. Typically QSTB* would be used to generate an interrupt to the controller.
The changer also provides three general status lines HELP*, CLOSE, and CHECK. HELP* when asserted indicates that a serious problem has occurred and the changer has dropped into test mode. CLOSE is asserted when a magazine is in place and the front door is closed. CHECK is asserted when the changer is powered up.
The player supplies 5V DC power to the connector, but the service manual claims it is only for test purposes. Basically they don't want you to draw a bunch of power from it.
The interface connector also has a pin to which you can connect the output of an IR receiver/demodulator such as the Sharp GP1U5X (or some such) which is available from Radio Shack. The unit will then respond to standard Sony CD remote codes, although this is of little use if you have more than one player, and it doesn't support direct access to any disc.
Last updated August 30, 2004
Copyright 1995, 2004 Eric Smith