RFID Communications

6.4.13 ABxS Command 85H: Read All

DESCRIPTION

Command 85H reads data from all RFID tags-in-field, or those tags with the specified Family ID.

DISCUSSION

This command is used to read segments of data from contiguous areas of tag memory. It is capable of handling up to 1 kByte of data transferred to 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 will return a syntax error message 21H. The Read All consists of Tag Family ID and Reserved Byte, a start address and number of bytes, followed by a timeout value and the message terminator, FFFFH. If the read length exceeds the last tag address, the controller returns a syntax error message 21H. The data read from the tag is returned in the LSB of the register, and the MSB is always 00H. A special termination packet (AAH FFH) is sent after the timeout expires. The controller returns a response after the timeout expires. The command returns a response after the successful operation or when the timeout expires.

Field

Remarks

Command

Command number in hex preceded by AAH

 

 

Tag Family

Tag Family ID - 00H = all tags

 

 

Reserved Byte

00H

 

 

Start Address

Tag address where the read will start

 

 

Read Length

Number of tag addresses to be read

 

 

Timeout

Timeout value given in 1 ms units (001EH - FFFEH)

 

 

Message Terminator

FFFFH

 

 

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LRP2000 Passive Reader/Writer

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Escort LRP2000 manual ABxS Command 85H Read All