AR0234 kernel driver for NVIDIA Jetson

NVIDIA Jetson kernel driver for Onsemi AR0234, a 2.3 MP global shutter 1/2.6" CMOS sensor.

• 2-lane MIPI CSI-2
• 10-bit RAW output
• 1920×1200 @ 60 fps

AR0234 camera modules are available at kurokesu.com

Setup

Install required tools:

sudo apt install -y --no-install-recommends dkms

Clone this repository:

cd ~
git clone https://github.com/Kurokesu/ar0234-jetson-driver.git
cd ar0234-jetson-driver/

Run setup script:

sudo ./setup.sh

Setup script:

• Fetches NVIDIA device tree headers required for build
• Builds and installs kernel module via DKMS
• Builds and copies device tree overlay (.dtbo) to /boot
• Installs ISP tuning to /var/nvidia/nvcam/settings/

Use Jetson-IO to configure CSI connector:

sudo /opt/nvidia/jetson-io/jetson-io.py

Navigate through the menu:

1. Configure Jetson CSI Connector (named "22pin" on 6.2.2, "24pin" on 6.2.1)

2. Configure for compatible hardware

3. Select port configuration:

   • Camera AR0234-A - cam0
   • Camera AR0234-C - cam1
   • Camera AR0234 Dual - cam0 + cam1

   

4. Save pin changes

5. Save and reboot to reconfigure pins

After reboot, verify sensor is detected:

sudo dmesg | grep ar0234

Expected output (dual):

nv_ar0234: module verification failed: signature and/or required key missing - tainting kernel
ar0234 9-0010: tegracam sensor driver:ar0234_v2.0.6
tegra-camrtc-capture-vi tegra-capture-vi: subdev ar0234 9-0010 bound
ar0234 10-0010: tegracam sensor driver:ar0234_v2.0.6
tegra-camrtc-capture-vi tegra-capture-vi: subdev ar0234 10-0010 bound

Signature warning is expected since DKMS modules are unsigned.

Image output

GStreamer

Single:

gst-launch-1.0 -e nvarguscamerasrc sensor-id=0 ! \
   'video/x-raw(memory:NVMM),width=1920,height=1200,framerate=30/1' ! \
   queue ! nvvidconv ! queue ! nveglglessink

Dual:

gst-launch-1.0 -e \
   nvarguscamerasrc sensor-id=0 ! \
      'video/x-raw(memory:NVMM),width=1920,height=1200,framerate=30/1' ! \
      queue ! nvvidconv ! queue ! nveglglessink \
   nvarguscamerasrc sensor-id=1 ! \
      'video/x-raw(memory:NVMM),width=1920,height=1200,framerate=30/1' ! \
      queue ! nvvidconv ! queue ! nveglglessink

nvgstcapture

nvgstcapture-1.0 --sensor-id 0

Trigger modes

AR0234 supports two external trigger modes. Both use TRIG pin on camera module as external signal input. TRIG is a 1.8 V logic level input wired directly to sensor. Trigger pulse only initiates capture, exposure time remains controlled by sensor's integration time register.

TRIG and FLASH signals are available on AUX connector:

Full module pinout and AUX connector part number are documented in 234x-CSI wiki page.

trigger_mode	Description
0	Off (free-running, default)
1	External trigger (pulsed/automatic)
2	Sync-sink

external-trigger

Sensor stays in standby and waits for activity on TRIG pin. Exposure and readout happen sequentially: readout does not begin until exposure is complete. Two sub-modes are available:

• Pulsed: each high pulse on TRIG pin captures a single frame (minimum pulse width 125 ns, 3 EXTCLK cycles at 24 MHz). Frame rate is determined by pulse frequency.
• Automatic: if TRIG signal stays high, sensor outputs frames continuously at configured frame rate.

echo 1 | sudo tee /sys/module/nv_ar0234/parameters/trigger_mode

After enabling trigger mode, start sensor stream via v4l2. Frames will arrive when there is signal on TRIG.

v4l2-ctl -d /dev/video0 --set-ctrl override_capture_timeout_ms=-1 --stream-mmap --stream-count=1000 --stream-to=/dev/null

Without override_capture_timeout_ms=-1 capture fails if first trigger arrives later than default 2.5 s VI timeout. On Argus path use enableCamInfiniteTimeout=1 instead.

sync-sink

Sensor streams continuously but locks frame timing to external TRIG signal. Unlike external-trigger, exposure and readout overlap (pipelined), so higher framerates are possible. Trigger period must not be shorter than configured frame length.

echo 2 | sudo tee /sys/module/nv_ar0234/parameters/trigger_mode

Disable trigger

echo 0 | sudo tee /sys/module/nv_ar0234/parameters/trigger_mode

Flash output

AR0234 has a FLASH output pin (1.8 V logic level) that goes HIGH during sensor exposure, useful for synchronizing external illumination such as strobes or LEDs.

Parameter	Type	Description
flash	bool	Enable flash output on FLASH pin
flash_delay	int	Signed delay (-127..127), negative = lead, positive = lag

Enable flash output:

echo Y | sudo tee /sys/module/nv_ar0234/parameters/flash

Flash signal start can be shifted relative to exposure using flash_delay:

• Negative values (lead): flash starts before exposure, extending total flash time
• Positive values (lag): flash starts after exposure begins, shortening total flash time

flash_delay accepts values from -127 to 127, where each unit is approximately 6.8 µs (2-lane).

# Flash starts ~68 µs before exposure (2-lane)
echo -10 | sudo tee /sys/module/nv_ar0234/parameters/flash_delay

# Flash starts ~68 µs after exposure begins (2-lane)
echo 10 | sudo tee /sys/module/nv_ar0234/parameters/flash_delay

Disable flash output:

echo N | sudo tee /sys/module/nv_ar0234/parameters/flash

Test mode

AR0234 has a built-in test pattern generator for verifying data validity.

Enable test pattern:

# 100% color-bar test pattern (test_mode = 2)
echo 2 | sudo tee /sys/module/nv_ar0234/parameters/test_mode

Disable test pattern:

echo 0 | sudo tee /sys/module/nv_ar0234/parameters/test_mode

Test pattern code	Description
0	Off (normal operation)
1	Solid color
2	100% color bar
3	Fade-to-grey color bar
256	Walking 1s (10-bit)

ISP tuning

Tuning file carries ISP parameters for this sensor: black level, white balance and color correction. Lens shading is left disabled. Global camera_overrides.isp applies to every camera and would shadow it, so setup retires it to camera_overrides.isp.bak.

Setup installs a file per badge, kurokesu_front_234CSI.isp and kurokesu_rear_234CSI.isp, so each camera on a dual board resolves its own.

To restore default ISP parameters, remove tuning files and restart Argus:

sudo rm /var/nvidia/nvcam/settings/kurokesu_front_234CSI.isp
sudo rm /var/nvidia/nvcam/settings/kurokesu_rear_234CSI.isp
sudo systemctl restart nvargus-daemon

Development builds

For manual builds without DKMS:

make              # build everything (dtbo + kernel module)
sudo make install # copy dtbo to /boot, rmmod + insmod

Note

Module is loaded immediately via insmod but won't persist across reboots. Use sudo ./setup.sh for permanent installation via DKMS.

Individual targets:

make dtbo      # build only the device tree overlay
make module    # build only the kernel module
make clean     # remove build artifacts

Build artifacts are placed in ./build.