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Exposure times can be selected that are possible under the current frame period selected. The
default frame period is 40ms (25Hz). From Figure 6 below, you can see that for this frame period,
XCAP enables the user to select exposure times in the range of 0-32ms in low gain and 0-26.5ms in
high gain.
This is due to the readout time in both gain modes. The relationship between the frame period,
exposure time and readout time is stated below, which applies for all frame periods set:
Frame period = Exposure Time - Readout Time
Therefore, the maximum possible exposure time with a 40ms frame period is:
LOW GAIN: Max. Exposure Time = 40ms - 7.5ms (readout time in low gain)
= 32.5ms
HIGH GAIN: Max. Exposure Time = 40ms - 13.5ms (readout time in high gain)
= 26.5ms
Figure 5: Gain, Exposure and Frame Period Controls.
Figure 6: Frame Period and Exposure Time Controls (Low Gain left, High Gain right).
Toggle the auto exposure
control on and off.
Adjust the frame period
from 16.7ms to 100ms (10-
60Hz frame rate
specification).
If the ALC is disabled, the
user can manually set a
fixed exposure time.
Set the gain mode (high or
low gain).
If the ALC is disabled, the
user can manually set a
fixed digital gain.
