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SmartOne C User Manual
Confidential & Proprietary Information
9100-0410-01 R2.4
A simple ACK or NAK from the SmartOne Device to the host (smart sensor):
ACKs.
AA 05 26 <crc crc> (for the Truncated message)
AA 05 27 <crc crc> (for the Raw message)
NAK:
AA 05 FF <crc crc> (NAK).
NOTE:
As the SmartOne operates, some debugging traces come out of the serial port. Those traces should simply
be ignored. Once the handshake line is pulled low, the unit is in “command mode” and debugging traces will stop.
NOTE:
User commands will ALWAYS be responded to immediately with either an acknowledgement or a NAK
(as shown in the examples above). Once an acknowledgement (or NAK) is received, the host should simply
ignore the serial port until the next time it sends a command.
NOTE:
The most common reasons for a NAK are incorrect CRC, incorrect length field, or incorrect command
field (i.e. not 0x26 or 0x27 for truncated and raw respectively).
THE HANDSHAKE LINE
The handshake line should be pulled low before sending each serial message. The recommended use of the
handshake line is:
1. Pull handshake low.
2. Wait 2-3 milliseconds.
3. Send command
4. Receive response.
5. Raise handshake high.