AR0833 Datasheet, PDF (46/64 Pages) ON Semiconductor – 8 Mp CMOS Digital Image Sensor

AR0833: 1/3.2-Inch 8 Mp CMOS Digital Image Sensor
Integration Time for Interlaced HDR Readout
Global Reset Release (GRR)
Global reset release mode allows the integration time of the AR0833 to be controlled by
an external electromechanical shutter. GRR mode is generally used in conjunction with
ERS mode. The ERS mode is used to provide viewfinder information, the sensor is
switched into GRR mode to capture a single frame, and the sensor is then returned to
ERS mode to restore viewfinder operation.
Overview of Global Reset Release Sequence
The basic elements of the GRR sequence are:
1. By default, the sensor operates in ERS mode and the SHUTTER output signal is LOW.
The electromechanical shutter must be open to allow light to fall on the pixel array.
Integration time is controlled by the coarse_integration_time register.
2. A global reset sequence is triggered.
3. All of the rows of the pixel array are placed in reset.
4. All of the rows of the pixel array are taken out of reset simultaneously. All rows start to
integrate incident light. The electromechanical shutter may be open or closed at this
time.
5. If the electromechanical shutter has been closed, it is opened.
6. After the desired integration time (controlled internally or externally to the AR0833),
the electromechanical shutter is closed.
7. A single output frame is generated by the sensor with the usual LV, FV, PIXCLK, and
DOUT timing. As soon as the output frame has completed (FV negates), the electrome-
chanical shutter may be opened again.
8. The sensor automatically resumes operation in ERS mode.
This sequence is shown in Figure 32. The following sections expand to show how the
timing of this sequence is controlled.
Figure 32: Overview of Global Reset Sequence
ERS Row Reset
Integration
Readout ERS
AR0833_DS Rev. H Pub. 4/15 EN
46
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