Section 3

Communication Protocol

The AT83SND2CMP3 is remotely controlled using simple ‘user interface like’ commands such as Play or Stop commands. The communication protocol provides an abstraction of the physical layer between the Remote Controller and the Player.

3.1Communication The communication protocol is a half-duplex protocol between a host Remote Controller

Protocol

and the AT83SND2CMP3 (Player) over a UART.

 

Note: In the following discussion, Remote Controller is considered as a ‘master’ and Player as

 

a ‘slave’.

3.2Frame Format

All the commands at physical layer level shall respect the following frame format:

Figure 3-1 .Communication Protocol Frame Format

Frame Start

Channel

Protocol

Data

7Eh

FFh

Command

Length

 

 

 

 

Data

CheckSum

The frame format breaks down into the following information:

Frame Start (1 byte): Synchronization character 7Eh

Channel (1 byte): logical channel number (reserved and set to FFh)

Protocol command (1 byte): refer to command set list.

Data Length (1byte): data length in byte excluding the Checksum byte.

AT83SND2CMP3 User Guide

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7525A–MP3–07/05