CXD2434TQ View Datasheet(PDF) - Sony Semiconductor

Part Name

Description

Manufacturer

CXD2434TQ

Timing Generator for Progressive Scan CCD Image Sensor

Sony Semiconductor 

CXD2434TQ

3. External trigger mode

External trigger mode starts exposure in sync with the external trigger input. No special pins are required to

set this mode.

The IC prepares to shift to external trigger mode with the falling edge of the TRIG pin (Note). The timing to

shift to external trigger mode varies according to the mode setting. (See the table.) The BUSY pin maintains

high status during external trigger mode. Whether or not to discharge the vertical CCD charge is set by

FSE.

Note) See the detection timing for VD, TRIG, EFS and ESG.

Mode settings during external trigger (Note 1)

PS SMD1 SMD2

Description of operation

L

L

X The IC is shifted to external trigger mode by HD, exposure is finished after the set

H

L

H time, and XSG is output. (Note 2)

The IC is shifted to external trigger mode by HD, exposure is finished 1/50 s later,

H

L

L

and XSG is output.

The IC is shifted to external trigger mode by VD and exposure is finished in sync

X

H

L

with VD after the set time. (Note 2)

X

H

H Trigger input is not accepted.

Note 1) The SMD1 and SMD2 setting method varies according to the PS status. See “2. Electronic shutter”.

PS = Low: Set by serial input.

PS = High: Set by the SMD1 and SMD2 pins.

Note 2) The exposure time setting method is the same as the exposure time setting for the electronic shutter.

<FSE and discharge operation>

During external trigger mode, the previously exposed signal charge sometimes remains in the vertical CCD

when exposure finishes. In this case, the image shot with external trigger mode is output overlapped with the

previously shot image. Setting FSE to high performs discharge operation for signal charges remaining in the

vertical CCD after trigger input. Discharge operation is not performed when FSE is low. This setting is only

valid when SMD1 is low.

<Finishing the exposure period with ESG>

During external trigger mode, exposure can be finished in sync with the falling edge of ESG (Note). If SMDE

is set to low, the XSG pulse is output regardless of the electronic shutter setting, when the falling edge of

ESG is detected. ESG should be fixed to high status at all times other than during external trigger mode. Do

not change SMDE while BUSY is high.

Note) See the detection timing for VD, TRIG, EFS and ESG.

<Signal after external trigger mode>

After high-speed external trigger mode is finished, the exposure time differs from that performed by the

electronic shutter setting. This is because the start and finish of external trigger mode are not synchronized

to VD input.

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