Camera Link Requirements
Each channel link is composed of 5 LVDS pairs:
- One LVDS pair transmits the clock to the frame grabber.
- Four LVDS pairs transmit the payload to the frame grabber at a bit rate equal to the clock frequency multiplied by 7.
The following requirements apply to each channel link separately.
Clock Line Requirements
For each channel link individually, the clock signal must satisfy the following requirements:
- Clock frequency range: 20 to 85 MHz.
- The clock may not be switched off during normal operation.
- For correct operation of PoCL, it is mandatory to apply the clock as soon as possible after power on. The time-out delay is 500 milliseconds.
- The clock jitter must be as low as possible; it is recommended to use X-Tal oscillators to generate the Camera Link clock. It may not exceed 1 ns or 20% of the clock period.
- The clock duty cycle must be better than 25%/75%.
Data Lines Requirements
For each channel link individually, the electrical signal of the 4 data lines must be conform to the Camera Link requirements, namely be generated by a National Semiconductor chip as specified in the Table A-1 of the Camera Link Specification v1.1.
Cable Requirements
The camera cables must be Camera Link compliant and terminated with a MiniCL connector at the frame grabber side.
Both PoCL and non-PoCL cables can be used.
The usage of poor quality Camera Link cables may cause malfunction. This becomes critical for systems with a high clock rate or with long cables length. Therefore, Euresys recommends using Camera Link cables that are certified by the cable manufacturer for the length vs. clock rate combination.
Multiple Channel Links Requirements
For configurations using more than 1 channel link, it is mandatory to follow the additional requirements:
- The Camera Link standard specifies that all four enable signals are supplied to all channel links using the Medium and the Full configurations. For the 80-bit configuration, only the LVAL signal needs to be distributed on the second and the third channel link.
- In any configuration, the same LVAL signal must be applied on all channel link involved in the configuration
- At least one valid LVAL pulse needs to be sent to the frame grabber before it can start acquiring data.
- The skew across LVAL signals of all channel link receivers involved in the configuration may not exceed 2 ns (about 40 cm of cable). It is recommended to:
- Use identical cables in terms of length and propagation delay characteristic for both connectors.
- Apply the LVAL signal when power is on.