User's Manual

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3 Commands list
Commands are exchanged with the module using the protocol described above. All frames contain a
command byte and command arguments. Depending upon the command, arguments can be optional, so
a command length can be in the range from 1-1024 bytes.
3.1 Generic commands
3.1.1 Acknowledge frame (0x00)
This is the response message from the module to the host. This frame always contains 1-byte with
command ID and optional arguments.
Command description:
Argument
Size
Value
Description
Command ID
1
0x00
Related command
ID
1
X
Related command code
Other parameters n X
Depending on the requested command this parameter is n
-
bytes long and contains parameters
Example:
HOST=>READER: 0x02 – GET_TAG_COUNT command
READER=>HOST: 0x00 - ACK byte
0x02 - related command code GET_TAG_COUNT
0x01 – argument for GET_TAG_COUNT – 0x01 – one tag
detected
3.1.2 Error response (0xFF)
In case of any problems with executing the command, the device can send back ERROR response with error
number returned by the RFID chip. The most common errors are described below.
If the host sends an Error frame without argument to the reader, then repeat last frame.
Command description
Argument
Size
Value
Description
ACK
1
0x00
Command ID
(optional)
1
0x01
DUMMY_COMMAND
Example:
HOST=>READER: 0xFF – Error byte
READER=>HOST: XX XX XX … - last command send to the host
Example:
READER=>HOST: 0xFF – Error byte
0x01 - related command code DUMMY_COMMAND
0x02 – layer byte
0x01 – Error number