Fairchild CAM/CMOS-2K.LS - Manual (Page 22)

ExSync
Camera Input
LineValid
Camera Output
Notes specific to this mode
1 Unlike Freerunning mode, the user triggers (separately) both the CAM/CMOS - 2K.LS readout cycle, and the CAM/CMOS - 2K.LS
reset-&-integration cycle. All of the modes other than Freerunning mode allow the user to do this
2 The user initiates a readout cycle by taking ExSync low as shown above. Readout actually begins a time
"t
XFR
" after ExSync is taken low, and lasts 2048 clock cycles
3 The user can read data from the CAM/CMOS - 2K.LS while LineValid is high as shown above and explained in Figure 3.4.1
4 The reset-&-integration cycle to be read out in the next period "n+1" is initiated by ExSync returning high;
integration begins when reset is complete a time "t
Reset
" after ExSync goes high, and continues
for the remainder of "t
LinePeriod
". The user can therefore shorten integration time by increasing "t
Hold
" above
5 The line period is set by the user by returning ExSync low, thereby initiating the next "n+1th" readout cycle
6 The minimum time that ExSync can be held low is "t
MinSync
" as shown above
7 Integration is cut off when the user takes ExSync low again as shown in the waveforms above
8 The line period must be greater than or equal to "t
Readout"
plus t
Xfr
", which sets maximum line rate to 50K lines/sec
9 If the user brings the ExSync Camera Input low prior to "tXFR" + "tReadout" after ExSync goes low, then the CAM/CMOS
2K.LS delays initiation of the "n+1th" readout cycle until "t
Readout
"+ "t
XFR
" has elapsed after ExSync last went low
Figure 3.4.2 -- Mode 2: ExSync Synchronization
...gives the user asynchronous hardware control over initiation of the camera readout cycle
and over termination of the line period...
...separately gives the user asynchronous hardware control
t
XFR
t
LinePeriod
t
Readout
2048 Clock Cycles
t
Reset2
t
Integration
n
n+1
Data Camera Output
Strobe Camera Output
Line Valid Camera Output
1 2 3 1023 1024
>t
MinSync
t
Hold
Fairchild Imaging • CAM/CMOS-2K.LS Line Scan Camera User’s Manual • Rev C• 22 of 42