Enable Signals
The standard defines 4 enable signals:
- FVAL —Frame Valid— is defined HIGH for valid lines.
- LVAL —Line Valid— is defined HIGH for valid pixels.
- DVAL —Data Valid— is defined HIGH when data is valid.
- Spare has been defined for future use.
The standard requires that all four enable signals are provided by the camera to all channel links.
The enable signals are used differently according to the selected acquisition mode.
Acquisition mode |
FVAL usage |
LVAL usage |
DVAL usage |
Spare usage (*) |
Area-scan |
Start of frame |
Start of line |
Clock enable (optional) |
Unused |
Line-scan |
Unused |
Start of line |
Clock enable (optional) |
Unused |
Raw grabbing |
Frame cover |
Unused |
Clock enable (optional) |
Unused |
(*) The spare signal is always ignored.