Camera Link interface (O1-O4 or CL1, CL2)
Bonito Technical Manual
V2.2.1
27
Camera Link interface (O1-O4 or CL1,
CL2)
Camera Link is an interface for the transmission of digital video data. The
standard defines data transfer on a physical base and determines connectors,
cables and components for transmission and reception. Three different
configurations (base, medium and full) are available, distinguished by the
number of transmitter–receiver pairs (one, two or three respectively). While the
base configuration is able to operate with one cable, for the medium and the
full configuration two cables between camera and grabber are necessary.
Each transmitter–receiver channel implements the so called
Channel Link
technology. One Channel Link transmitter serializes 28 parallel data bits in a
ratio of 7:1 and transfers them via five differential signal pairs (four data pairs
plus one for the clock). By using the LVDS (Low Voltage Differential Signaling)
standard, net parallel clock rates up to 85 MHz (up to 595 Mbit/s on the wire
pairs) can be achieved.
The Camera Link standard also defines further non-serialized signals. There are
four direct camera control lines (CC1 – CC4) from frame grabber to the camera,
as well as a bi-directional asynchronous serial communication channel, all of
them transmitted using the LVDS standard.
Due to the high bandwidth requirements the Bonito makes use of an extension
to the Camera Link Full standard.
Camera Link Full defines 8 ports with 8 bits each. Thus it has a payload of 64 bits
which – including synchronization signals – only occupy 76 of the 3 x 28 = 84
available transmitter bits. By incorporating the unused bits and some
redundant synchronization signals, it is possible to transmit 10 x 8 = 80 bits
net. This is also known as Camera Link 10-tap standard with 80 bits.
One Camera Link 80-bit channel provides enough bandwidth to achieve nearly
200 frames per second at four megapixels per frame. To reach the 400 frames
per second the Bonito uses two Camera Link 80-bit channels in parallel.
Camera link connectors and 10-tap pin
assignment
The Bonito implements two Camera Link 80-bit channels in 10-tap configura-
tion grouped at the connector pairs O2/O1 and O4/O3 respectively. The
Bonito
CL-400B/C 200fps
cameras implement only one Camera Link 80-bit channel at
the connector pair CL1/CL2.
