RFID Communications

Example

Writes 41H—the ASCII character "A"—to all tags with family code 03H, starting at address 0005H for the next consecutive 40 Bytes. A timeout of 2 seconds (07D0H = 2000 x 1 msec increments) is set for the completion of the configuration. In this example, four tags are found and filled successfully.

Command from Host

Field

Content

Header

0202H

 

 

Command Size

000AH

 

 

Command Code

84H

 

 

Family Code

03H

 

 

Reserved

00H

 

 

Start Address

0005H

 

 

Number of Bytes

0028H

 

 

Timeout, 2 seconds

07D0H

 

 

Data Value Byte

41H

 

 

Checksum

27H

 

 

Terminator

03H

 

 

Response from Controller

Field

Content

Header

0202H

 

 

Response Size

0003H

 

 

Command Echo

84H

 

 

Numbers of Tags

04H

 

 

Status Byte

08H

 

 

Checksum

6CH

 

 

Terminator

03H

 

 

6.5.13 ABxF Command 85H: Block Read All

DESCRIPTION

Command 85H reads a block of data from all RFID tags-in-field or all those with the specified family code.

DISCUSSION

This command is used to read segments of data from contiguous areas of tag memory. The timeout value is given in 1 msec increments and can have a value of 1EH to FFFEH (65,534 ms). When the timeout is set to 0, the controller returns a syntax error. The Block Read All consists of a family code, the reserved byte, a start address and length, followed by a timeout value, and a message terminator as shown below. If the read length exceeds the last tag address, the controller returns an syntax error message (error code 21H). A special termination packet is sent when the timeout expires. A response is returned after successful completion of the operation or when the timeout expires.

Field

Content

Header

0202H

 

 

Command Size

Packet length in bytes excluding the header, command size, checksum, and terminator bytes.

 

 

Command

85H

 

 

Family Code

Tag Family Code - 00H = all tags

 

 

Reserved

Ignored byte, set to 00H

 

 

Start Address

2-byte value for the starting tag address

 

 

Number of Bytes

2-byte value for the number of bytes to be read

 

 

Timeout

2-byte value for timeout in 1 ms units (1EH - FFFEH)

 

 

Checksum

Optional checksum

 

 

Terminator

03H

 

 

107

LRP2000 Passive Reader/Writer

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Escort LRP2000 manual ABxF Command 85H Block Read All, 107