RFID Communications
61 LRP2000 Passive Reader/Writer
6.4.2 ABxS Command 05H: Read
DESCRIPTION
Read data from contiguous bytes of the RFID tag's read/write memory.
DISCUSSION
This command is used to read bytes from contiguous areas of tag memory. The minimum length of the
data read from the tag is 1 byte. The maximum is the entire read/write address space of the tag. The
timeout value is given in 1 ms increments and can have a value of 001EH to FFFEH (65,534 ms). When
the timeout is set to 0, the controller returns a syntax error. The Read command consists of a start address
and length, followed by the message terminator, FFFFH, as shown below. If the read range exceeds the
last tag address, the controller returns error message 21H, invalid format. The data read from the tag is
returned in the least significant byte (LSB) of the word, and the most significant byte (MSB) is always 00H.
Example
The goal is to read the eight bytes of data from the tag starting at address 1. A timeout of 2 seconds
(07D0H = 2000 x 1 ms increments) is set for the completion of the Read.
Field Remarks
Command Command number in hex preceded by AAH
Start Address Tag address where the read starts
Read Length Number of tag addresses to be read
Timeout Timeout value given in 1 ms units (001EH - FFFEH)
Message Terminator FFFFH
Command From Host Response from Controller
MSB LSB Remarks MSB LSB Remarks
AAH 05H Perform Command 5 AAH 05H Command Echo
00H 01H Start Byte Address = 0001H 00H 52H Read Data 1 =52H
00H 08H Read Length = 8 bytes 00H 46H Read Data 2 =46H
07H D0H 2-second Timeout 00H 49H Read Data 3 =49H
FFH FFH Message Terminator 00H 44H Read Data 4 =44H
00H 20H Read Data 5 =20H
00H 54H Read Data 6 =54H
00H 61H Read Data 7 =61H
00H 67H Read Data 8 =67H
FFH FFH Message Terminator