RFID Communications
75 LRP2000 Passive Reader/Writer
6.4.14 ABxS Command 86H: Write All
DESCRIPTION
Command 86H writes data to all RFID tags, or all tags with the same Family ID.
DISCUSSION
This command is used to write segments of data to contiguous areas of tag memory. It is capable of
transferring up to 1 kByte of data from the Host with one command. 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 Write consists of a Tag Family ID and an Reserved Byte, start
address followed by the data stream to be written to the RFID tag. If the write range exceeds the last tag
address, the controller returns error message 21H, invalid format. The data to be written to the tag is
contained in the LSB of the register, and the MSB is always 00H. The controller returns a response when
the timeout expires. The controller returns a response when the timeout expires.
Example
Writes four bytes of data, starting at address 0001H. A timeout of 2 seconds (07D0H = 2000 x 1 ms
increments) is set for the completion of the Write. The Family ID byte is set to 2, so all tags with Family ID
of 2 are written to (four tags in this example).
Field Remarks
Command Command number in hex preceded by AAH
Family ID Tag Family ID - 00H = all tags
Reserved 00H
Start Address Tag address where the write will start
Write Length Number of tag addresses to be written to in bytes
Timeout Timeout value given in 1 ms units (001EH - FFFEH)
Write Data Data to be written
Message Terminator FFFFH
Command from host Response from controller
MSB LSB Remarks MSB LSB Remarks
AAH 86H Perform Command 86 AAH 86H Command Echo
02H 00H Tag Family/Reser ved 04H 08H Ntags/Status
00H 01H Start Address FFH FFH Message Terminator
00H 04H Write Length
07H D0H Timeout
00H 40H Data byte 1
00H 41H Data byte 2
00H 42H Data byte 3
00H 43H Data byte 4
FFH FFH Message Terminator