OPT8320 Datasheet, PDF (16/88 Pages) Texas Instruments – OPT8320 3D Time-of-Flight Sensor

OPT8320
SBAS748 – DECEMBER 2015
www.ti.com
7.3.2.3 Shutter Operation
Shutter operation can be used to control the exposure to ambient light. The shutter switch separates the charge
storage node from the pixel charge collection node. The shutter can be programmed to become inactive (switch
is on) at the start of integration and become active (switch is off) at the end of integration time to avoid collection
of unwanted ambient light during the sensor readout. The behavior of the shutter switch is shown in Table 11.
Table 11. Shutter Operation
OPERATION
RESET
QUAD STATE
INTEGRATION
READOUT
State of the shutter software with the shutter operation
enabled (default)
On
On
Off
State of the shutter software with the shutter operation
disabled
On
On
On
QUAD DEAD
TIME
Off
On
The SHUTTER_EN parameter enables or disables the shutter operation. The SHUTTER_EN description is given
in Table 12.
PARAMETER
SHUTTER_EN
Table 12. Shutter Operation Registers
DEFAULT
0
DESCRIPTION
Set to 1 to enable shutter operation.
7.3.3 Modulation Block
The OPT8320 modulation block provides the high-frequency demodulation to the pixels as well as the
illumination module. The modulation block controls the phase between the modulation signals connected to the
pixels and the illumination module from quad to quad.
7.3.3.1 Sensor Output Signals
The phase between illumination modulation and the sensor demodulation signals is stepped automatically as per
the quad number illustrated in Figure 6. Because the OPT8320 uses four quads per modulation frequency, the
phase is typically stepped between 0º, 90º, 180º, and 270º. The phase stepping sequence of the sensor is
programmable through the OPT8320 registers. A different sequence can be enabled for odd and even sub-
frames. Also, the phase registers for the base frequency and de-aliasing frequency are separately
programmable. The OPT8320 output signals are listed in Table 13.
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