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RFID Communications
6.4.22 ABxS Command 95H: SN Read
DESCRIPTION
Command 95H reads data from a specified RFID tag.
DISCUSSION
This command is used to read segments of data from contiguous areas of tag memory. It is capable of handling up to 48 bytes of data transferred to the host with one command if there is no tag Family ID. 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 SN Read consists of a start address, length, and timeout value followed by a serial number. The
Field | Remarks |
Command | Command number in hex preceded by AAH |
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Tag Family | Tag Family ID - 00H = all tags |
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Reserved | 00H |
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Start Address | Tag address where the read will start |
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Read Length | Numbers of tag addresses to be read |
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Timeout | Timeout value given in 1 ms units (001EH - FFFEH) |
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Tag Serial Number | The |
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Message Terminator | FFFFH |
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Example
Reads four bytes of data from the tag specified by serial number starting at address 0001H. A timeout of 2 seconds (07D0H = 2000 x 1 ms increments) is set for the completion of the SN Read. The Family ID byte is set to zero.
Command from Host
MSB | LSB | Remarks |
AAH | 95H | Perform Command 95 |
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00H | 00H | Tag Family 00/Reserved |
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00H | 01H | Start Address |
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00H | 04H | Read Length |
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07H | D0H | |
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00H | ABH | SN byte 0 |
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00H | 02H | SN byte 1 |
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00H | F3H | SN byte 2 |
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00H | 05H | SN byte 3 |
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00H | 00H | SN byte 4 |
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00H | 01H | SN byte 5 |
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00H | 04H | SN byte 6 |
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00H | E0H | SN byte 7 |
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FFH | FFH | Message Terminator |
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Response from Controller
MSB | LSB | Remarks |
AAH | 95H | Command Echo |
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00H | 30H | Data byte 1 |
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00H | 31H | Data byte 2 |
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00H | 32H | Data byte 3 |
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00H | 33H | Data byte 4 |
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FFH | FFH | Message Terminator |
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85 | LRP2000 Passive Reader/Writer |