OPT8320 Datasheet, PDF (14/88 Pages) Texas Instruments – OPT8320 3D Time-of-Flight Sensor

OPT8320
SBAS748 – DECEMBER 2015
www.ti.com
7.3.1.4 Integration Time
Integration time is the time that the sensor demodulation and the illumination modulation are active. The
configurable parameters are listed in Table 7.
PARAMETER
INTG_DUTY_CYCLE
INTG_DUTY_CYCLE_
SET_FAILED
Table 7. Integration Time Parameters
DEFAULT
13
0
DESCRIPTION
This parameter controls the ratio of integration time to total frame time.
This flag indicates if the INTG_DUTY_CYCLE setting has taken effect. If the
INTG_DUTY_CYCLE is not feasible for a given set of conditions, this flag is set.
This flag is cleared when a feasible value of INTG_DUTY_CYCLE is programmed.
If this flag is set, a lower value of INTG_DUTY_CYCLE must be programmed and
the value of the flag checked again. This process must be repeated until the flag
clears.
The INTG_DUTY_CYCLE registers allows 64 settings from 0 to 63. The relationship between effective
integration duty cycle of the base frame and the register value is given by Equation 5:
INTG_DUTY_CYCLE = ^{Integration Duty Cycle u64}
100
(5)
Internally, the INTG_DUTY_CYCLE value is clamped to a minimum of 1. Maximum integration duty cycle is given
by Equation 6:
PIX_CNT_MAX Reset Time + Readout Time
Maximum Integration Duty Cycle =
PIX_CNT_MAX
(6)
The INTG_DUTY_CYCLE parameter must be reprogrammed whenever any of the registers related to frame rate
control or region of interest are programmed. The related registers are:
• SUB_FRAME_CNT_MAX1
• SUB_FRAME_CNT_MAX2
• PIX_CNT_MAX
• LUMPED_DEAD_TIME
• ROW_START
• COL_START
• ROW_END
• COL_END
When the OPT8320 is in slave mode, the duty cycle still corresponds to the frame length calculated as per the
internal registers and not as per the period of the external sync signal. The sync signal period must be large
enough to make sure that the frame data are streamed successfully. When the sync signal period is larger than
the internal frame period, the actual integration duty cycle is less than the programmed value.
7.3.1.4.1 High Dynamic Range Functionality
When frame alternation is enabled, alternate frames can use different integration times. The supplementary
frame integration time is scaled down as compared to the base frame by a factor. The relevant parameters are
listed in Table 8.
PARAMETER NAME
SUP_FRM_INTG_SCALE
Table 8. High Dynamic Range Functionality Parameter
DEFAULT
63
DESCRIPTION
Denotes the percentage of INTG_PHASE in the supplementary frame in terms
of the base frame. INTG_DUTY_CYCLE2 = INTG_DUTY_CYCLE1 ×
(SUP_FRM_INTG_SCALE + 1) / 64.
The supplementary frame integration time is given in Equation 7:
Supplementary Frame Integration Time =
Base Frame Integration Time u ^{SUP_FRM_INTG_SCALE + 1}
64
(7)
14
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