RFID Communications
LRP2000 Passive Reader/Writer 114
After the controller sends the acknowledgment, it sends the read data from the two tags.
6.5.18 ABxF Command 91H: Memory Lock All
DESCRIPTION
Command 91H locks contiguous blocks of read-write memory. Once bytes are locked, they cannot be
written to, nor can they be unlocked.
DISCUSSION
The memory can be locked only in contiguous blocks. The command passes one parameter for the first
block, and another parameter for the number of blocks to be locked. This is one of only two ABx
commands that address the memory of the tag using these parameters. The block structure of the tags is
governed by the ISO-15693 specification. ABx command 15H can be used to obtain the memory
organization for a particular tag. Attempting to write to locked bytes returns a Write Security Error.
Field Content
Header 0202H
Response Size 0005H
Command Echo/Tag 1 8DH
Data from Address 0001H 05H
Data from Address 0002H AAH
Data from Address 0003H 21H
Data from Address 0004H 44H
Checksum 59H
Terminator 03H
Header 0202H
Response Size 0003H
Command Echo/Tag 2 8DH
Data from Address 0001H 05H
Data from Address 0002H AAH
Data from Address 0003H 21H
Data from Address 0004H 44H
Checksum 59H
Terminator 03H
Field Content
Header 0202H
Command Size Command length in bytes excluding the header, command size, checksum, and terminator bytes.
07H for this command.
Command 91H
Family Code Tag Family ID - 00H = all tags
Reserved Ignored byte, set to 00H
Timeout Timeout value given in 1 ms units
Starting Block First block of memory to be locked
Number of Blocks Number of blocks that will be locked
Checksum Optional checksum
Message Terminator 03H