RFID Communications
6.5 ABx Fast Protocol
The ABx Fast protocol differs from the Abx Standard Protocol in that the atomic data element is a byte instead of a
Packet Size
The ABx Fast protocol requires that the size of the packet be included following the terminator in every packet. All parameters and data between the packet size byte and the checksum (if used), or terminator bytes (if not using the checksum) must be accounted for in the packet size word. The packet size will be the same with or without a checksum.
Checksum
The optional checksum must be enabled from the operating mode menu to be available. The checksum is calculated by adding all the byte values in the packet (less the values in the header, checksum if present, and terminator), discarding byte overflow, and subtracting the byte sum from FFH. Thus, when the packet length through the checksum are added as byte values, the sum will be FFH.
Example
The following is a typical command using a checksum.
Field | Contents |
Header | 0202H |
|
|
Command Size | 0003H |
|
|
Command Code | 01H |
|
|
Timeout | 07D0H |
|
|
Checksum | 24H |
|
|
Terminator | 03H |
|
|
LRP2000 Passive Reader/Writer | 90 |