Example Of The Format Of A Serial Message - FLIR TAU User Manual

Appendix B—Serial Communication Technical Details
B.4.1 Byte Count Bytes
• On all incoming and outgoing messages, the Byte-Count Bytes are used to specify
the total number of data bytes in the packet. (Note: the number of data bytes in the
packet is not equal to the total number of bytes in the packet. For example, a No-Op
serial command contains zero data bytes.)
• The Byte Count must be an even number from 0 to 0x1F4 (500 decimal).
B.4.2 CRC Bytes
• On all incoming and outgoing messages, two cyclical redundancy checks (CRCs) are
calculated using CCITT-16 initialized to 0.
• CRC1 is calculated using only the first 6 bytes of the packet.
• CRC2 is calculated using all previous bytes in the packet (i.e. bytes 0 through N).
B.5

Example of the format of a serial message

Table B-5 describes the bytes that are transferred when the FFC_MODE_SELECT (0x0B)
command is issued to the camera to set the mode to Auto (0x01) and to get the FFC mode:
Table B-5: Sample FFC_MODE_SELECT (0x0B) Command
Set Message sent to camera:
Process
Status
Code
0x6E 0x00
Response from camera to set message:
Process
Status
Code
0x6E 0x00
Get Message sent to camera:
Process
Status
Code
0x6E 0x00
Response from camera to get message:
Process
Status
Code
0x6E 0x00
B-10
Reserved Function Byte Count
0x00 0x0B 0x00 0x02
Reserved Function Byte Count
0x00 0x0B 0x00 0x02
Reserved Function Byte Count
0x00 0x0B 0x00 0x00
Reserved Function Byte Count
0x00 0x0B 0x00 0x02
April 2009
Tau User's Manual
CRC Data
0x0F 0x08 0x00 0x01 0x10 0x21
CRC Data
0x0F 0x08 0x00 0x01 0x10 0x21
CRC Data
0x2F 0x4A 0x00 0x00
CRC Data
0x0F 0x08 0x00 0x01 0x10 0x21
TAU-0035-00-10, version 100
CRC
CRC
CRC
CRC