5.1.2. GPIO Control¶
Your OpenMV Cam has between 9 (OpenMV Cam M4) to 10 (OpenMV Cam M7) general purpose I/O pins onboard for talking to the real-world. We’re probably going to keep the pin count this low moving into the future to keep the OpenMV Cam tiny.
Anyway, there are a few ways to use GPIO pins.
18.104.22.168. As an Input¶
To use a GPIO pin as an input just do:
import pyb p = pyb.Pin("P0", pyb.Pin.IN) p.value() # Returns 0 or 1.
pyb.Pin() constructor creates a pin object which you will use to control
the I/O pin on your OpenMV Cam. The string you pass to the OpenMV Cam should be
P and then
0-8 for the OpenMV Cam M4 and
0-9 for the OpenMV Cam M7.
Once you’ve created the GPIO pin use the
pyb.Pin.value() method to get the
state of the IO pin.
p = pyb.Pin("P0", pyb.Pin.IN, pyb.Pin.PULL_UP)
22.214.171.124. As an Output¶
Now, to use a GPIO pin as an output just do:
import pyb p = pyb.Pin("P0", pyb.Pin.OUT_PP) p.high() # or p.value(1) to make the pin high (3.3V) p.low() # or p.value(0) to make the pin low (0V)
It’s that easy! However, what if you want to open-drain an output? Just do:
p = pyb.Pin("P0", pyb.Pin.OUT_OD)
pyb.Pin.high() will cause the pin to float while
pull the pin low. If you need a pull-up resistor on the Pin just add:
p = pyb.Pin("P0", pyb.Pin.OUT_OD, pyb.Pin.PULL_UP)
... to the constructor.