
RFID Communications
6.4.16 ABxS Command 88H: Tag Search All
DESCRIPTION
Command 88H checks to see if there is an RFID tag within range of the antenna.
DISCUSSION
This command activates controller to look for a tag in range. As soon as the controller finds a tag it returns a command echo to the host. 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 number of tags returned can be either 1 (tag found), or 0 (timeout expired without having found a tag).
Field | Remarks |
Command | Command number in hex preceded by AAH |
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Family ID | Tag Family ID - 00H = all tags |
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Reserved | 00H |
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Timeout | Timeout value given in 1 ms units (001EH - FFFEH) |
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Message Terminator | FFFFH |
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Example
Checks for an RFID tag in the RF field. A timeout of 1 seconds (07D0H = 2000 x 1 ms increments) is set for the completion of the Tag Search. The Family ID is set for any tag. One tag is found and the command is successful.
Command from Host
MSB | LSB | Remarks |
AAH | 88H | Perform Command 88 |
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00H | 00H | Family ID/Reserved |
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07H | D0H | |
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FFH | FFH | Message Terminator |
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Response from Controller
MSB | LSB | Remarks |
AAH | 88H | Command Echo |
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01H | 08H | Ntags/Status |
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FFH | FFH | Message Terminator |
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77 | LRP2000 Passive Reader/Writer |