24
Controlling the AM-4
network. See the
Web Page Setup
section for information on setting IP Address and
Unit ID.
AMINet Protocol
The user data sent in the UDP packet follows our AMINet Ethernet protocol.
AMINet was originally developed for use with our Ethernet Machine, which provides
an Ethernet backbone for communication between Alcorn McBride Show
Controllers. Now the same, easy to use protocol can be used to control the AM4.
AMINet is a very flexible and robust Ethernet protocol that allows for many different
uses; however, only one of AMINet’s command op-codes is necessary to transmit
commands to the AM4 making the usage very simple.
Control Message Format
The control source will send a UDP packet that contains a AM4 Control Message as
the User Data in the packet. A AM4 Control Message is comprised of a few bytes
needed specifically for AMINet and some Command bytes. The Command simply
needs to contain an Addressed Pioneer / AMI serial protocol command. For
example, A AM4 Control Message containing the Command bytes 7@?V<CR>
would cause the AM4 on the network with Unit ID 7 to send back a UDP packet
containing its version information. Please see the Pioneer / AMI Serial Protocol
section for detailed information about the rest of the command set.
The basic format of a AM4 Control Message is as follows:
0xF1 0x01 0x04 <Pioneer / AMI Serial Command> <Checksum> 0xF2
The only bytes that change from message to message are the Command bytes and the
Checksum. The command corresponds exactly to an Addressed Pioneer / AMI serial
command.
Control Message Checksum
The Checksum is the summation of the hexadecimal value of all of the bytes in the
Control Message except the first byte (0xF1), the last byte (0xF2) and of course the
Checksum itself. The value of the checksum may easily increase to a value that
cannot be represented by one byte. This situation calls for what we call number
expansion.
If the value of the Checksum is between 0x00 and 0xF9 (0-249), the value is
represented in only 8 bits (1 byte). If the value is between 0xFA and 0xFFFF (250-
65535), the value is represented in 16 bits (2 bytes) and is preceded by 0xFF to
signify the number has been expanded to 16 bits. If the value is between 0x10000
and 0xFFFFFF (65536-16777215), the value is represented in 24 bits (3 bytes) and is
preceded by 0xFE to signify the number has been expanded to 24 bits. The following
example shows a Control Message with an expanded Checksum.
0xF1 0x01 0x04 5
5 @ R J
<CR> 0xFF 0x01 0x58 0xF2
The value of the checksum is calculated by adding the hexadecimal values of each
byte preceding it except the first byte (0xF1) as follows:
0x01 + 0x04 + 0x35 + 0x35 + 0x40 + 0x52 + 0x4A + 0x0D = 0x158.
The Checksum in this example is 0x158, but because it is greater 0xF9, the two-byte
Checksum is preceded by 0xFF.
Содержание AM-4
Страница 1: ...AM 4 Digital Audio Machine Hardware and Software Reference Manual ...
Страница 2: ...ii Welcome PLACE HOLDER FOR THE BACK OF THE FRONT COVER DO NOT PRINT ...
Страница 3: ...Welcome iii Digital Audio Machine User s Guide Alcorn McBride Inc ...
Страница 6: ......
Страница 10: ...4 Quick Start Guide ...
Страница 32: ...26 Controlling the AM 4 ...
Страница 58: ...52 GPS Operation GPS Operation ...
Страница 70: ...64 Troubleshooting Guide FAQ ...
Страница 71: ...Mechanical Information 65 Mechanical Information Mechanical Dimensions Surface Mounting ...
Страница 74: ...68 Mechanical Information Rack Mount Kit 2 Unit Part Number 302 100704 ...