TAU-0640-00-10, version 110
June 2011
B-1
Appendix B Serial Communication Technical Details
B.1 Serial Communications Primary Interface
The camera is capable of being controlled remotely through an asynchronous serial interface
consisting of the signals named RX, TX, and GND using
3.3 volt
signal levels.
Note
B.2 Serial Communications Protocol
• The required serial port settings are shown in Table B-1.
• The camera does not generate an outgoing message except in reply to an incoming
message.
• The camera generates an outgoing reply to each incoming message.
• All messages, both incoming and outgoing, adhere to the packet protocol defined in
Table B-2 and the subparagraphs that follow. The first byte i.e., the Process byte is
transmitted first followed by the rest of the bytes in the order specified.
• All multi-byte arguments defined herein uses big-endian ordering (MSB first).
• The serial inter-byte timeout is factory set to 100ms
• Only use the function commands listed in Table B-4. Unsupported commands may
corrupt the camera's software.
• For reference only, a sample command and response is shown in Table B-5.
Example Process Code
Transmission is LSB first (for each byte) and most significant byte first on multi-byte
messages. All bytes are preceded by a zero start bit and followed by a one stop bit.
The camera core is designed to talk to a PC serial port directly and may seem inverted
if direct communication to a logic device is desired.
6E = 0 0111 0110 1 = Start bit, E with LSB first, 6 with LSB first, Stop bit
On an oscilloscope the observation is, Idle low but, zero high. Starting at idle, when the
signal goes high, that is the first 0; then two 0’s high, three 1’s low, one 0 high, two 1’s
low, one 0 high, one 1 low, (6E complete).
The camera is compatible with most RS232 drivers/receivers but does not implement
signaling levels compliant with the RS232 standard voltage levels.
Table B-1: Serial Port Settings
Parameter
Value
Baud rate:
57600
Data bits:
8
Parity:
None
Stop bits:
1
Flow control:
None
