Camera interfaces
192
Goldeye G/CL Technical Manual V4.2.0
Line Valid (LVAL)
The synchronization signal LVAL is used to indicate a line transfer phase within the
current frame transfer. When rising, it indicates the start of a new line transfer
phase. When falling, it indicates the end of the line transfer phase.
The LVAL signal is valid only while FVAL is high.
Data Valid (DVAL)
The synchronization signal DVAL is used to indicate a valid pixel within the current
line transfer phase. The DVAL bit is high for the transfer of one pixel. When high, it
indicates that the pixel is valid. If low, the pixel must be ignored. A pixel is only
valid, if all of the FVAL, LVAL and DVAL signals are high.
To make use of the DVAL signal, the frame grabber in use must be able to process
it.
Sequential overview
After the start of the data transfer, frames and lines are transferred using the
sequence as described.
1. The FVAL signal is set to
high
and indicates the start of a new frame transfer.
2. A gap occurs before the LVAL signal is set to
high
.
The length of this gap is controlled by the
ClMinFValToLValDelay
parameter
and is given in camera clock cycles.
The effective length of this gap is equal to either the value of
ClMinFValToLValDelay
, or (3
×
Width
+ 32) clock cycles,
whatever is the larger.
3. The LVAL signal is set to
high
and indicates the start of a new line transfer.
4. The LVAL signal switches back to
low
and indicates transfer of the line is
complete.
5. A gap occurs between two line transfers.
Figure 56: Camera Link data transfer
FVAL
LVAL
8
3
2
4
6
7
5
1
9
10
2
1
3
4
DVAL
