Bonito Technical Manual
V2.4.0
29
Camera interfaces
This is an open collector optocoupler output. The transistor is conductive during
the active exposure time of the image sensor. The optocoupler adds an intrinsic
delay to the signal.
The power dissipation through the optocoupler’s transistor must not exceed 150
mW.
A typical value for the external pull-up resistor is R = 4700
. This ensures risk-
free operation to the upper Vcc limit.
The start-of-exposure edge (falling edge at V
out
) is delayed for about 3 μs typi-
cally, the end-of-exposure edge for about 20 – 50 μs. The latter is mainly caused
by the storage time of the photo transistor and is strongly dependent on the
external pull-up resistor value R. To safely toggle the output between high and
low state use exposure times above 10 μs and also observe a gap of 50 μs or more
between two exposures. Faster rates may also work, but should be tested indi-
vidually. Consequently, in the default continuous mode (
M=0
) the output does
not toggle because the inter-exposure gap is too short.
Active exposure is also displayed by the
L3
indicator at the camera’s back side.
Reserve I/O (pin 5, 9 and 14-15)
Note
This output is not recommended for new system designs.
Use the synchronization output feature instead: see chapter
Synchronization output (pin 6)
Note
The pins 5, 9, 14 and 15 are reserved for future use. Do not con-
nect. Currently they have no function, but this may change.
