Protocol For Data Transmission And Reception; Basic Procedure; Communication Errors - Denon DN-C635 Service Manual

Revision1.0
Date 2003-01-28

2.1 Protocol for data transmission and reception

This device's serial protocol is based on half-duplex communication. Therefore the host shall
transmit commands and receive answers according to the following procedure.

Basic procedure

1) The host selects a prefer command and transmit codes to device. The host shall not send each
byte within 40µsec because the device cannot receive within 40µsec after previous byte.
2) The host shall wait device's answer before transmit next command. Reading RC, AC and PC
bytes, the host can get acknowledge whether the device received previous command correctly or
not.
3) When transmit the command which causes some functions, the host shall get device's status that
the device becomes ready. The Read Status command is used for this purpose.
4) The host shall complete the transmission of one command within 40 msec.
5) The device shall return answer within 5 seconds.
6) The device cannot receive any command within 2 second after power turned on.

Communication errors

1) In case of communication error such as overrun, framing, or parity error occurred, the device returns
NAK (15h) code within 80msec from the start of command transmission. When received NAK (0x15)
code, the host shall transmit previous command again immediately.
2) If the host detects communication error while receiving the answer, the host shall send NAK (0x15)
code within 80msec from beginning of receipt.
received NAK code within 80msec.
3) The host shall send previous command when there is no answer from device.
DN-C635 Serial Interface Specification
The device sends same answer again after
7 page of 39