NeoPixel library not working on the Jetson Nano 4gb

[Thesis123123]

Followed this guide for installing blinka

https://learn.adafruit.com/circuitpython-libraries-on-linux-and-the-nvidia-jetson-nano/initial-setup

and this guide for the neopixel

https://learn.adafruit.com/circuitpython-libraries-on-linux-and-the-nvidia-jetson-nano/neopixels-with-spi

Ran the blinka test with no errors or warning

import board
import digitalio
import busio

print("Hello blinka!")

# Try to great a Digital input
pin = digitalio.DigitalInOut(board.D4)
print("Digital IO ok!")

# Try to create an I2C device
i2c = busio.I2C(board.SCL, board.SDA)
print("I2C 1 ok!")
i2c = busio.I2C(board.SCL_1, board.SDA_1)
print("I2C 2 ok!")

print("done!")

jetson@jetson-desktop:~/MasterAPP$ python3.7 Blinkatest.py
Hello blinka!
Digital IO ok!
I2C 1 ok!
I2C 2 ok!
done!
Exiting... 
Cleaning up pins
jetson@jetson-desktop:~/MasterAPP$ 

And running the example code again for the strips

import time
import board
import neopixel_spi as neopixel

NUM_PIXELS = 12
PIXEL_ORDER = neopixel.GRB
COLORS = (0xFF0000, 0x00FF00, 0x0000FF)
DELAY = 0.1

spi = board.SPI()

pixels = neopixel.NeoPixel_SPI(
    spi, NUM_PIXELS, pixel_order=PIXEL_ORDER, auto_write=False
)

while True:
    for color in COLORS:
        for i in range(NUM_PIXELS):
            pixels[i] = color
            pixels.show()
            time.sleep(DELAY)
            pixels.fill(0)

Again no errors thrown by the program. The error below is when i did the cancaled the program with ctrl + c.

jetson@jetson-desktop:~/MasterAPP$ python3.7 Backlight.py
^CTraceback (most recent call last):
  File "/home/jetson/MasterAPP/Backlight.py", line 55, in <module>
    time.sleep(DELAY)
KeyboardInterrupt
Exiting... 
Cleaning up pins

Data pin is on pin 19 of the carrier board. Can confirm 5v power on the actual leg of the SK6812. I probed pin 19 with an oscilloscope and no signal was present. confirmed that spi/dev is also present

jetson@jetson-desktop:~/MasterAPP$ ls /dev/i2c* /dev/spi*
/dev/i2c-0  /dev/i2c-1  /dev/i2c-2  /dev/i2c-3  /dev/i2c-4  /dev/i2c-5  /dev/i2c-6  /dev/spidev0.0  /dev/spidev0.1  /dev/spidev1.0  /dev/spidev1.1
jetson@jetson-desktop:~/MasterAPP$ 

Nvidia Jetson nano 4GB, Ubuntu 18.04, Jetpack 4.6.4

I can confirm that the strips are working fine becuase when i used an RPi Pico with the adafruit neopixel library, it had no problem lighting up all the colors

Am i doing something wrong here? I looked at previous issues and one was similar but #31 but it was closed without any other comments on how it was fixed.

Any ideas what might have gone wrong?

[caternuson]

The error below is when i did the cancaled the program with ctrl + c

That's not an error. It's the expected stack trace when exiting via . It throws a KeyboardInterrupt exception. The actual code line referenced is just where the code was when was hit.

I probed pin 19 with an oscilloscope and no signal was present.

Probably using the wrong pin then. Are you probing physical pin 19, i.e. SPI1_MOSI? Or the pin that is digital IO 19, i.e D19?

[Thesis123123]

Probably using the wrong pin then. Are you probing physical pin 19, i.e. SPI1_MOSI? Or the pin that is digital IO 19, i.e D19?

Physical pin 19, the one where there is the number 19 written on the board

Which one should i be using?

[caternuson]

Hmm...that looks like the correct pin. @makermelissa any ideas? Does the Jetson require anything special for enabling SPI? Looks OK to me based on /dev entries. But don't have HW to test directly.

[makermelissa]

When I last checked it out, you did have to enable it. The guide explains here: https://learn.adafruit.com/circuitpython-libraries-on-linux-and-the-nvidia-jetson-nano/initial-setup#enable-uart-i2c-and-spi-3039597

It's possible things have changed since it's been a few years since I last updated the guide.

[Thesis123123]

When I last checked it out, you did have to enable it. The guide explains here: https://learn.adafruit.com/circuitpython-libraries-on-linux-and-the-nvidia-jetson-nano/initial-setup#enable-uart-i2c-and-spi-3039597

It's possible things have changed since it's been a few years since I last updated the guide.

Yes have done these step, and i just rechecked it, SPI1 are still checked.

I tried using i2c-6 and didnt have any problems, SPI seems to be the only one not working.

I even tried doing a blink test on pin 19 (D10).

import time
import board
import neopixel_spi as neopixel
import digitalio

led = digitalio.DigitalInOut(board.D10)
led.direction = digitalio.Direction.OUTPUT
 
while True:
    led.value = True
    time.sleep(0.5)
    led.value = False
    time.sleep(0.5)

The signal was there when i probed it

[Laura-VFA]

Hi there, did anyone solve this? I am struggling with the same problem :(

[klsetzer]

Hi there, did anyone solve this? I am struggling with the same problem :(

My and one of my colleagues have spent the last two days going down this road. We've followed the same steps as @Thesis123123 . One of us managed to get some activity on the spi1 bus, but it looks like random TTL noise, and the neopixel strip lights the first 5 leds randomly. Sometimes running the script gives no results on the neopixel strip.

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

import time
import board
import neopixel_spi as neopixel

NUM_PIXELS = 20
PIXEL_ORDER = neopixel.GRB
COLORS = (0xFF0000, 0x00FF00, 0x0000FF)
DELAY = 1.1

spi = board.SPI()

pixels = neopixel.NeoPixel_SPI(
    spi, NUM_PIXELS, pixel_order=PIXEL_ORDER, auto_write=False
)

for i in range(NUM_PIXELS):
    pixels[i] = 0xFF0000
    pixels.show()
time.sleep(9999)