EPC901 Datasheet, PDF (14/37 Pages) Espros Photonics corp – CCD line sensor 1024x1 pixel

It is to note that the CCD continues to be photo-sensitive during the shift operation i.e. for a time T_SHIFT after the falling edge of SHUTTER.
5.3. Multi frame acquisition
Up to 4 images can be acquired and stored in the CCD frame store in a fast sequence without intermediate read-out. The CCD frame store
is organized in 4 CCD frame store elements (FS1-FS4), thereby each CCD frame store element can store one frame/image. The first
captured image initially occupies 3 frame store elements as for a single-frame acquisition (see section 5.2 and Figure 8). epc901 automati-
cally detects a multi-frame acquisition when detecting the second SHUTTER signal without prior read-out. Upon the second shutter the
first image is shifted to a single frame store element (see (2) in Figure 9). The frames are shifted from the CCD pixel field to and through
the CCD frame store in a FIFO-manner i.e. the first captured image is the first one read out. The read-out is described in more detail in
section 5.4. As soon as 4 frames have been captured without prior read-out, at least one read-out has to be issued prior the next shutter in
order to make FS1 available again. Excessive shutter pulses are ignored.
SHUTTER
DATA_RDY
READ_CLK
T
SHIFT
T
SHIFT
T
CDS
T
SHIFT
T
CDS
T
CDS
(1)
(2)
(3)
(4)
Figure 9: Illustrative example of multi-frame acquisition and read-out
5.4. Image readout
After one or more images have been captured, the first image (FIFO) can be read out through the video interface on the pins VIDEO_P
and VIDEO_N. The read-out is controlled by the READ pin. The following timing diagram shows its usage:
READ
VIDEO_P/N
T_CDS
T_{RD_PULSE}
Pre-loading of
internal pipe-line
T_{RD_CLK}
1
2
3
P
0
PP
12
P
3
T_H,VIDEO
P
N
DATA_RDY READY goes low when the readout of
the last stored frame begins
ANA_TEST0
(rising edge indicates readout of the last pixel in a frame)
N * T _{RD_CLK}
RD_CLK
Figure 10: Image readout timing of one frame
The first pulse of a read sequence applied to pin READ is a Read Pulse and must have a duration of T . RD_PULSE Upon a Read Pulse, the last
frame in the CCD frame store is sampled pixel-wise onto a capacitor array thereby the pixel charges are converted into pixel voltages
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Characteristics subject to change without notice
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Datasheet_epc901-V5.6
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