Hello,
I have a 2.9 Flexible 296x128 Monochrome eInk / ePaper Display [UC8151D Chipset] : ID 4262 : $24.95 : Adafruit Industries, Unique & fun DIY electronics and kits connected to the Adafruit eInk Breakout Friend which I want to use with a NVIDIA Jetson Nano Development Kit B01. The Nano is running JetPack 4.6.1 and was freshly set up.
To test the display, I first tried it with a Raspberry Pi 4B. I set it up with the following steps:
sudo apt update && sudo apt upgrade -y && sudo apt autoremove -y
sudo apt install python3-pip -y
sudo pip3 install --upgrade setuptools
cd ~
sudo pip3 install --upgrade adafruit-python-shell
wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/raspi-blinka.py
ls /dev/i2c* /dev/spi*
wget https://learn.adafruit.com/pages/12762/elements/2993427/download -O blinkatest.py && python3 blinkatest.py
sudo pip3 install adafruit-circuitpython-epd
wget https://github.com/adafruit/Adafruit_CircuitPython_framebuf/raw/main/examples/font5x8.bin
sudo pip3 install adafruit-circuitpython-neopixel
I then connected to pins of the display to the 40 pin header of the Raspberry Pi:
- VIN → 3.3V
- GND → GND
- SCK → Pin 23 (GPIO11 / SPI_CLK)
- MOSI → Pin 19 (GPIO10 / SPI_MOSI)
- ECS → Pin 24 (GPIO08 / SPI_CE0_N)
- D/C → Pin 15 (GPIO22 / GPIO_GEN3)
- RST → Pin 13 (GPIO27 / GPIO_GEN2)
- BUSY → Pin 11 (GPIO17 / GPIO_GEN0)
After that I tested it using a simple Python script.
import digitalio
import busio
import board
from adafruit_epd.epd import Adafruit_EPD
spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
ecs = digitalio.DigitalInOut(board.CE0)
dc = digitalio.DigitalInOut(board.D22)
rst = digitalio.DigitalInOut(board.D27)
busy = digitalio.DigitalInOut(board.D17)
srcs = None
from adafruit_epd.uc8151d import Adafruit_UC8151D
display = Adafruit_UC8151D(128, 296, spi, cs_pin=ecs, dc_pin=dc, sramcs_pin=srcs, rst_pin=rst, busy_pin=busy)
display.set_black_buffer(1, True)
display.set_color_buffer(1, True)
display.rotation = 3
display.fill(Adafruit_EPD.WHITE)
display.text("Hello World!", 0, 0, Adafruit_EPD.BLACK, font_name='font5x8.bin', size=1)
display.display()
And it worked like expected. After that I switched to the Jetson Nano and installed the library using the following steps:
sudo apt update && sudo apt upgrade -y && sudo apt autoremove -y
sudo apt install python3-pip
sudo /opt/nvidia/jetson-io/jetson-io.py # activate SPI and reboot
sudo pip3 install --upgrade setuptools
pip3 install adafruit-blinka
pip3 install adafruit-circuitpython-epd
pip3 install Jetson.GPIO==2.0.21 # Use previous version because of the bugs with the latest version
wget https://github.com/adafruit/Adafruit_CircuitPython_framebuf/raw/main/examples/font5x8.bin
sudo modprobe spidev # enable SPI for use
I switched the connections to the Jetson Nano but didn’t change the pins since they should be compatible. However the display does not update nor flash / blink. The script runs without error but I cannot check the serial connection using an oscilloscope. I am grateful for any ideas on how the debug this problem.
Thanks in advance!
– Edit –
It looks like SPI is not enabled on the gpios. When I run sudo cat /sys/kernel/debug/tegra_gpio it returns:
Name:Bank:Port CNF OE OUT IN INT_STA INT_ENB INT_LVL
A: 0:0 64 40 40 24 00 00 000000
B: 0:1 f0 00 00 60 00 00 000000
C: 0:2 1f 00 00 1d 00 00 000000
D: 0:3 00 00 00 00 00 00 000000
E: 1:0 40 00 00 00 00 00 000000
F: 1:1 00 00 00 00 00 00 000000
G: 1:2 0c 00 00 04 00 00 000000
H: 1:3 fd 99 00 60 00 00 000000
I: 2:0 07 07 03 02 00 00 000000
J: 2:1 00 00 00 00 00 00 000000
K: 2:2 00 00 00 00 00 00 000000
L: 2:3 00 00 00 00 00 00 000000
M: 3:0 00 00 00 00 00 00 000000
N: 3:1 00 00 00 00 00 00 000000
O: 3:2 00 00 00 00 00 00 000000
P: 3:3 00 00 00 00 00 00 000000
Q: 4:0 00 00 00 00 00 00 000000
R: 4:1 00 00 00 00 00 00 000000
S: 4:2 a0 80 00 00 00 00 000000
T: 4:3 01 01 00 00 00 00 000000
U: 5:0 00 00 00 00 00 00 000000
V: 5:1 01 00 00 00 00 00 000000
W: 5:2 00 00 00 00 00 00 000000
X: 5:3 78 08 08 70 00 60 606000
Y: 6:0 06 00 00 02 00 00 000000
Z: 6:1 0f 08 08 04 00 06 020600
AA: 6:2 00 00 00 00 00 00 000000
BB: 6:3 01 00 00 00 00 00 000000
CC: 7:0 92 80 80 00 00 12 121200
DD: 7:1 01 00 00 00 00 00 000000
EE: 7:2 00 00 00 00 00 00 000000
FF: 7:3 00 00 00 00 00 00 000000
There shouldn’t C: 0:2 1f 00 00 1d 00 00 000000 instead be like C: 0:2 00 00 ...?
I enabled SPI via sudo /opt/nvidia/jetson-io/jetson-io.py however I also pushed a 0 into the register at 0x6000d008 and it still does not work?