CoaXPress v1.0 | v1.1 | v1.1.1

CoaXPress specifications meet de demands of high-speed vision applications, such as machine vision, medical imaging, life sciences and global security. CXP data transmission is scalable over single or multiple coaxial cables for even higher speeds. For communication from the host, a 20Mbps uplink enables device control and configuration. CXP also provides the device with power over the cable.

Frame Grabbers support all frequencies up to a specified speed (CXP-1, CXP-2, CXP-3, CXP-5 or CXP-6)
Cameras will typically use the lowest possible speed.

Low speed uplink

CoaXPress supports a low speed uplink channel from frame grabber to camera. This uplink channel has a fixed bit rate of 20.833 Mbit/s. The uplink channel uses 8b/10b encoding. The uplink can be used for camera control, triggering and firmware updates. When using the multilane DIN 1.0/2.3 cabling solution an optional high speed uplink can also be used, allowing 6.25 Gbit/s uplink communication to the camera. This can be used for very accurate triggering.

Cabling and connectors

The transmission medium for CoaXPress is a coaxial cable with a characteristic impedance of 75 Ω. The maximum transmission distance is depending on the bit rate and the quality of the cable. RG11, RG6, RG59 and other cable types can be used. It is also possible to reuse existing coaxial cable when upgrading from an analogue to a digital camera system.

The standard connector for CoaXPress is a 75 Ω BNC connector. A second connector option is the DIN 1.0/2.3 connector. Solutions with a 5W5 connector have also been demonstrated, but this is not officially supported by the CoaXPress consortium.

Implementation

CoaXPress compatible driver and equalizer devices must be used with FPGA devices, in order to implement CoaXPress standard protocol. Such standard implementation is executed using FPGA IP core, specially designed for this protocol, while it takes care of all the features defined by standard. Each side of the vision system, e.g. Camera or frame grabber, requires dedicated FPGA IP core.

CoaXPress supports a low speed uplink channel from frame grabber to camera. This uplink channel has a fixed bit rate of 20.833 Mbit/s. The uplink channel uses 8b/10b encoding. The uplink can be used for camera control, triggering and firmware updates.

When using the multilane DIN 1.0/2.3 cabling solution an optional high speed uplink can also be used, allowing 6.25 Gbit/s uplink communication to the camera. This can be used for very accurate triggering.