
9 RS-232 interface definition for DVC1310A / 1312A
cameras (LVDS Cameras Only)
9.1 INTRODUCTION
The following is a definition of the RS-232 interface for the DVC-1310A/1312A cameras. RS-232
control is standard within all DVC131X cameras that use LVDS outputs to connect with suitable
frame grabber boards; it can be controlled via a communication program (such as Windows
HyperTerminal) or within a larger program, such as C-View
.
9.2 PHYSICAL
DESCRIPTION
The RS-232 interface is physically designed as a microprocessor-based circuit that is present on-
board the DVC-131X camera. The microprocessor has an on-board UART which communicates
with the serial port of the PC via an RS232 interface chip. The microprocessor is configured to
have two data ports: a 4-bit data output register that controls the camera modes and an 11-bit data
output register that controls the exposure of the camera. In addition to the data ports, a dual digital-
to-analog converter (DAC) is used to control the camera gain and offset by creating two 0-to-3V
analog control voltages. The microprocessor decodes valid camera commands and creates the user
specified combination of the two data ports and the two analog control voltages.
9.3 COMMUNICATION
PROTOCOL
Serial communication protocol: the camera uses a full duplex UART type asynchronous system,
using standard non-return-to-zero (NRZ) format (one start bit, eight data bits, one stop bit, no
parity). The baud rate is fixed at 9600. The character code is based on the ASCII standard.
Character flow protocol: None
Command Syntax: the camera will recognize a command as three command characters, followed
by a space character, followed by an argument that consists of two characters, ended by the
carriage return character.
Query Syntax: the camera will recognize a query as three command characters followed by the
question mark character, then ended by the carriage return character. The camera responds to a
query with three command characters, followed by a space character, followed by an argument that
consists of three characters, then ended by the carriage return character.
Error messages: the camera responds to an erroneous command or query in one of three possible
ways.
ERROR MESSAGE
EXPLANATION
E-SYN
The camera cannot understand the command
E-ARG
The camera can understand the command, but the argument is either out-of-
range or not understood e.g. an alpha character embedded in a numeric string
E-XMT
The camera detects a transmission error e.g. buffer overflow, parity or
framing.
E-HRT
The HRT command was issued in a mode in which Hardware Reset is illegal.
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