Simple test

Ensure your device works with this simple test.

examples/pca9685_simpletest.py
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# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

# This simple test outputs a 50% duty cycle PWM single on the 0th channel. Connect an LED and
# resistor in series to the pin to visualize duty cycle changes and its impact on brightness.

from board import SCL, SDA
import busio

# Import the PCA9685 module.
from adafruit_pca9685 import PCA9685

# Create the I2C bus interface.
i2c_bus = busio.I2C(SCL, SDA)

# Create a simple PCA9685 class instance.
pca = PCA9685(i2c_bus)

# Set the PWM frequency to 60hz.
pca.frequency = 60

# Set the PWM duty cycle for channel zero to 50%. duty_cycle is 16 bits to match other PWM objects
# but the PCA9685 will only actually give 12 bits of resolution.
pca.channels[0].duty_cycle = 0x7FFF
examples/pca9685_calibration.py
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# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

# This advanced example can be used to compute a more precise reference_clock_speed. Use an
# oscilloscope or logic analyzer to measure the signal frequency and type the results into the
# prompts. At the end it'll give you a more precise value around 25 mhz for your reference clock
# speed.

import time

from board import SCL, SDA
import busio

# Import the PCA9685 module.
from adafruit_pca9685 import PCA9685

# Create the I2C bus interface.
i2c_bus = busio.I2C(SCL, SDA)

# Create a simple PCA9685 class instance.
pca = PCA9685(i2c_bus)

# Set the PWM frequency to 100hz.
pca.frequency = 100

input("Press enter when ready to measure default frequency.")

# Set the PWM duty cycle for channel zero to 50%. duty_cycle is 16 bits to match other PWM objects
# but the PCA9685 will only actually give 12 bits of resolution.
print("Running with default calibration")
pca.channels[0].duty_cycle = 0x7FFF
time.sleep(1)
pca.channels[0].duty_cycle = 0

measured_frequency = float(input("Frequency measured: "))
print()

pca.reference_clock_speed = pca.reference_clock_speed * (
    measured_frequency / pca.frequency
)
# Set frequency again so we can get closer. Reading it back will produce the real value.
pca.frequency = 100

input("Press enter when ready to measure coarse calibration frequency.")
pca.channels[0].duty_cycle = 0x7FFF
time.sleep(1)
pca.channels[0].duty_cycle = 0
measured_after_calibration = float(input("Frequency measured: "))
print()

reference_clock_speed = measured_after_calibration * 4096 * pca.prescale_reg

print("Real reference clock speed: {0:.0f}".format(reference_clock_speed))
examples/pca9685_servo.py
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# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time

from board import SCL, SDA
import busio

# Import the PCA9685 module. Available in the bundle and here:
#   https://github.com/adafruit/Adafruit_CircuitPython_PCA9685
from adafruit_motor import servo
from adafruit_pca9685 import PCA9685

i2c = busio.I2C(SCL, SDA)

# Create a simple PCA9685 class instance.
pca = PCA9685(i2c)
# You can optionally provide a finer tuned reference clock speed to improve the accuracy of the
# timing pulses. This calibration will be specific to each board and its environment. See the
# calibration.py example in the PCA9685 driver.
# pca = PCA9685(i2c, reference_clock_speed=25630710)
pca.frequency = 50

# To get the full range of the servo you will likely need to adjust the min_pulse and max_pulse to
# match the stall points of the servo.
# This is an example for the Sub-micro servo: https://www.adafruit.com/product/2201
# servo7 = servo.Servo(pca.channels[7], min_pulse=580, max_pulse=2350)
# This is an example for the Micro Servo - High Powered, High Torque Metal Gear:
#   https://www.adafruit.com/product/2307
# servo7 = servo.Servo(pca.channels[7], min_pulse=500, max_pulse=2600)
# This is an example for the Standard servo - TowerPro SG-5010 - 5010:
#   https://www.adafruit.com/product/155
# servo7 = servo.Servo(pca.channels[7], min_pulse=400, max_pulse=2400)
# This is an example for the Analog Feedback Servo: https://www.adafruit.com/product/1404
# servo7 = servo.Servo(pca.channels[7], min_pulse=600, max_pulse=2500)
# This is an example for the Micro servo - TowerPro SG-92R: https://www.adafruit.com/product/169
# servo7 = servo.Servo(pca.channels[7], min_pulse=500, max_pulse=2400)

# The pulse range is 750 - 2250 by default. This range typically gives 135 degrees of
# range, but the default is to use 180 degrees. You can specify the expected range if you wish:
# servo7 = servo.Servo(pca.channels[7], actuation_range=135)
servo7 = servo.Servo(pca.channels[7])

# We sleep in the loops to give the servo time to move into position.
for i in range(180):
    servo7.angle = i
    time.sleep(0.03)
for i in range(180):
    servo7.angle = 180 - i
    time.sleep(0.03)

# You can also specify the movement fractionally.
fraction = 0.0
while fraction < 1.0:
    servo7.fraction = fraction
    fraction += 0.01
    time.sleep(0.03)

pca.deinit()