Denon DCM 390 Serial Protocol - Page 6

Revision1.40 Date 24.May.'07 DCM390 Serial Interface Specification 6 page of 40 2.1 Protocol for data transmission and reception This unit is based on half-duplex communication. The unit shall therefore transmit commands and receive answers according to the following procedure. Basic procedure 1) The host shall select commands for this unit and transmit them to this unit. Command interval time is MIN 40µsec. 2) Having issued a command, the host shall receive an answer from this unit, and then issue the next command. 3) The host shall analyze the RC, AC, and PC as answers given and decide whether the command has been normally executed. 4) The host shall give an answer to a command that gives operational instructions, then issue a status request command, and decide whether this unit has finished operating with regard to the command that gives operational instructions. 5) The time from the start of command transmission to the end of command transmission should be max 40 msec. 6) The time from the completion of command transmission to the start of answerback is MAX.5sec. 7) This unit cannot receive any commands for about 5 seconds after the power switch is turned on. Communication errors 1) Having received a command, which results in a communication error (overrun, framing, or parity error), this unit shall give NAK (15h). (MAX 80ms from the start of command transmission) 2) If the host has received NAK from this unit, it shall retransmit the command that it has transmitted immediately beforehand. 3) Having received an answer, which results in a communication error error), the host shall respond with NAK. (overrun, framing, or parity 4) If it has received NAK from the host, this unit shall retransmit the answer it has transmitted immediately beforehand. (MAX 40ms) 5) When there is no answer from the unit within 6s, the host shall retransmit the command. D&M