BOBCAT HD-SDI
Hardware User’s Manual
Imperx, Inc.
Rev. 1.4
6421 Congress Ave.
6/2/2014
Boca Raton, FL 33487
+1 (561) 989-0006
73 of 175
4.2.2.
Camera Serial Protocol
In order to access the camera registers and resources a sequence of bytes needs
to be transmitted to the camera via the Camera’s RS-232 serial interface. This
is an RS-232, asynchronous, full-duplex, serial protocol, with 1 start bit, 8 data
bits, 1 stop bit, no hand shake, and no parity – Figure 4.1. The default baud rate
is configurable (9600, 19200, 38400, 57600 and 115200 – default).
Figure 4.1– Serial protocol format.
Each camera control register can be updated independently. In terms of the
serial protocol, all registers are defined as 16-bit address (hex format), and 32-
bit data (hex format). Camera registers using less than 32-bits in width must be
padded with ‘0’s on writes, and unused bits are ignored on reads. Register data
is always “packed low” within 32-bit data words for registers defined less than
32-bits.
There is a latency delay for each command due to command execution and data
transmission over the serial port. This latency varies from command to
command because of resource location and command response length.
4.2.2.1.
Write Operation
In order to write to any given camera register, a sequence of 7 bytes should
be sent to the camera. If there is no error the camera returns one byte
acknowledge for the write command <Ack> - Figure 4.2. If there is an error
the camera returns two bytes not-acknowledge for the write command – the
first byte is <Nac> <Err>, the second is the error code – Figure 4.3, and
4.4:
Write to camera (7 Bytes): <Write_Cmd> <
Address
> <
Data
>
1
st
byte: 0x57 (Write Command)
2
nd
byte:
<
Register Address_High
> MSB
3
rd
byte:
<
Register Address_Low
> LSB
4
th
byte:
<
Register Data Byte 4
> MSB
5
th
byte:
<
Register Data Byte 3
> …
6
th
byte:
<
Register Data Byte 2
> …
7
th
byte:
<
Register Data Byte 1
> LSB
Write Acknowledge (1 Byte): <Ack>
1
st
byte: 0x06 (Acknowledge)
