RFID Communications
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.
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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Start Address | Tag address where the write will start |
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Write Length | Number of tag addresses to be written to in bytes |
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Timeout | Timeout value given in 1 ms units (001EH - FFFEH) |
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Write Data | Data to be written |
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Message | Terminator FFFFH |
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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).
Command from host
MSB | LSB | Remarks |
AAH | 86H | Perform Command 86 |
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02H | 00H | Tag Family/Reserved |
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00H | 01H | Start Address |
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00H | 04H | Write Length |
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07H | D0H | Timeout |
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00H | 40H | Data byte 1 |
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00H | 41H | Data byte 2 |
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00H | 42H | Data byte 3 |
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00H | 43H | Data byte 4 |
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FFH | FFH | Message Terminator |
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Response from controller
MSB | LSB | Remarks |
AAH | 86H | Command Echo |
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04H | 08H | Ntags/Status |
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FFH | FFH | Message Terminator |
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75 | LRP2000 Passive Reader/Writer |