AR0141CS datasheet(23/64 Pages) ONSEMI

23 / 64 page

AR0141CS/D Rev. 6, 4/16 EN

©Semiconductor Components Industries, LLC, 2016.

AR0141CS: 1/4-Inch Digital Image Sensor

Sensor Readout

Image Acquisition Modes

The AR0141CS supports two image acquisition modes:

• Electronic rolling shutter (ERS) mode

This is the normal mode of operation. When the AR0141CS is streaming, it generates

frames at a fixed rate, and each frame is integrated (exposed) using the ERS. When the

ERS is in use, timing and control logic within the sensor sequences through the rows

of the array, resetting and then reading each row in turn. In the time interval between

resetting a row and subsequently reading that row, the pixels in the row integrate inci-

dent light. The integration (exposure) time is controlled by varying the time between

row reset and row readout. For each row in a frame, the time between row reset and

row readout is the same, leading to a uniform integration time across the frame. When

the integration time is changed (by using the two-wire serial interface to change regis-

ter settings), the timing and control logic controls the transition from old to new inte-

gration time in such a way that the stream of output frames from the AR0141CS

switches cleanly from the old integration time to the new while only generating

frames with uniform integration. See “Changes to Integration Time” in the AR0141CS

• Global reset mode

This mode can be used to acquire a single image at the current resolution. In this

mode, the end point of the pixel integration time is controlled by an external electro-

mechanical shutter, and the AR0141CS provides control signals to interface to that

shutter.

The benefit of using an external electromechanical shutter is that it eliminates the visual

artifacts associated with ERS operation. Visual artifacts arise in ERS operation, particu-

larly at low frame rates, because an ERS image effectively integrates each row of the pixel

array at a different point in time.

Window Control

The sequencing of the pixel array is controlled by the x_addr_start, y_addr_start, x_ad-

dr_end, and y_addr_end registers.

Readout Modes

Horizontal Mirror

When the horiz_mirror bit (R0x3040[14]) is set in the read_mode register, the order of

pixel readout within a row is reversed, so that readout starts from x_addr_end + 1 and

ends at x_addr_start. Figure 21 on page 24 shows a sequence of 6 pixels being read out

with R0x3040[14] = 0 and R0x3040[14] = 1.

AR0141CS Datasheet(PDF) 23 Page - ON Semiconductor