From adafruit_servokit_ import ServoKit. PCA9685

Hello.
I am trying to drive a servo motor on my Jetson Nano with a PCA9685 PWM card.

These are the specs for my 4.6 jetpack.

steven@steven-desktop:~$ sudo apt-cache show nvidia-jetpack
Package: nvidia-jetpack
Version: 4.6-b199
Architecture: arm64
Maintainer: NVIDIA Corporation
Installed-Size: 194
Depends: nvidia-cuda (= 4.6-b199), nvidia-opencv (= 4.6-b199), nvidia-cudnn8 (= 4.6-b199), nvidia-tensorrt (= 4.6-b199), nvidia-visionworks (= 4.6-b199), nvidia-container (= 4.6-b199), nvidia-vpi (= 4.6-b199), nvidia-l4t-jetson-multimedia-api (>> 32.6-0), nvidia-l4t-jetson-multimedia-api (<< 32.7-0)
Homepage: Autonomous Machines | NVIDIA Developer
Priority: standard
Section: metapackages
Filename: pool/main/n/nvidia-jetpack/nvidia-jetpack_4.6-b199_arm64.deb
Size: 29368
SHA256: 69df11e22e2c8406fe281fe6fc27c7d40a13ed668e508a592a6785d40ea71669
SHA1: 5c678b8762acc54f85b4334f92d9bb084858907a
MD5sum: 1b96cd72f2a434e887f98912061d8cfb
Description: NVIDIA Jetpack Meta Package
Description-md5: ad1462289bdbc54909ae109d1d32c0a8

Package: nvidia-jetpack
Version: 4.6-b197
Architecture: arm64
Maintainer: NVIDIA Corporation
Installed-Size: 194
Depends: nvidia-cuda (= 4.6-b197), nvidia-opencv (= 4.6-b197), nvidia-cudnn8 (= 4.6-b197), nvidia-tensorrt (= 4.6-b197), nvidia-visionworks (= 4.6-b197), nvidia-container (= 4.6-b197), nvidia-vpi (= 4.6-b197), nvidia-l4t-jetson-multimedia-api (>> 32.6-0), nvidia-l4t-jetson-multimedia-api (<< 32.7-0)
Homepage: Autonomous Machines | NVIDIA Developer
Priority: standard
Section: metapackages
Filename: pool/main/n/nvidia-jetpack/nvidia-jetpack_4.6-b197_arm64.deb
Size: 29356
SHA256: 104cd0c1efefe5865753ec9b0b148a534ffdcc9bae525637c7532b309ed44aa0
SHA1: 8cca8b9ebb21feafbbd20c2984bd9b329a202624
MD5sum: 463d4303429f163b97207827965e8fe0
Description: NVIDIA Jetpack Meta Package
Description-md5: ad1462289bdbc54909ae109d1d32c0a8

When I do a connection test between the PCA9685 and my Jetson Nano it shows that it can be connected well.

steven@steven-desktop:~$ sudo i2cdetect -y -r 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: – – – – – – – – – – – – –
10: – – – – – – – – – – – – – – – –
20: – – – – – – – – – – – – – – – –
30: – – – – – – – – – – – – – – – –
40: 40 – – – – – – – – – – – – – – –
50: – – – – – – – – – – – – – – – –
60: – – – – – – – – – – – – – – – –
70: 70 – – – – – – –

but when running the library I get an error.

steven@steven-desktop:~$ python3
Python 3.6.9 (default, Mar 15 2022, 13:55:28)
[GCC 8.4.0] on linux
Type β€œhelp”, β€œcopyright”, β€œcredits” or β€œlicense” for more information.

from adafruit_servokit import ServoKit
Traceback (most recent call last):
File β€œβ€, line 1, in
File β€œ/usr/local/lib/python3.6/dist-packages/adafruit_servokit.py”, line 35, in
import board
File β€œ/usr/local/lib/python3.6/dist-packages/board.py”, line 39, in
import adafruit_platformdetect.constants.boards as ap_board
File β€œ/usr/local/lib/python3.6/dist-packages/adafruit_platformdetect/init.py”, line 10, in
from .board import Board
File β€œ/usr/local/lib/python3.6/dist-packages/adafruit_platformdetect/board.py”, line 24
from future import annotations
^
SyntaxError: future feature annotations is not defined

Can you help me please.
Thank you

I don’t have expericne with this PCA9685, you may try to find if similar issues happend at those threads: Search results for β€˜PCA9685 Nano’ - NVIDIA Developer Forums

1 Like

Adafruit libraries are updated frequently, but they do not always work with Jetson.
Downgrade the library to find a version that works.
Example:

sudo pip3 install -U \
adafruit-circuitpython-busdevice==5.1.2 \
adafruit-circuitpython-motor==3.3.5 \
adafruit-circuitpython-pca9685==3.4.1 \
adafruit-circuitpython-register==1.9.8 \
adafruit-circuitpython-servokit==1.3.8 \
Adafruit-Blinka==6.11.1 \
Adafruit-GPIO==1.0.3 \
Adafruit-MotorHAT==1.4.0 \
Adafruit-PlatformDetect==3.19.6 \
Adafruit-PureIO==1.1.9 \
Adafruit-SSD1306==1.6.2
2 Likes

Thank you very much for your help, with the example it worked perfectly.
Problem solved.

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