Webcam

The PineCube can be powered by the host and communicate as a peripheral. First, you’ll need to a dual USB-A (male) cable to plug it into your computer. Note that the Micro-USB port can be used only for power because the data lines are not connected.

USB as an Ethernet gadget

Goal: To achieve fast (low latency) wired network connection via USB-A port of PineCube. PineCube will be shown as a network device when connected to a computer via USB-A port. You can set up the computer to be in the same network as PineCube and connect to PineCube via SSH and/or Stream Videos from it.

  1. Additional patch to PineCube device tree disable ehci0 and ohci0, enabling usb_otg device instead and setting dr_mode to otg. If otg is not working for you, try setting dr_mode to peripheral. On Armbian there is no need for disabling ehci0 and ohci0. Device tree can be edited via armbian-config tool on Armbian OS (armbian-config -> System -> DTC). Example DTC on Armbian:

                    usb@1c19000 {
                            compatible = "allwinner,sun8i-h3-musb";
                            reg = <0x1c19000 0x400>;
                            clocks = <0x03 0x1d>;
                            resets = <0x03 0x11>;
                            interrupts = <0x00 0x47 0x04>;
                            interrupt-names = "mc";
                            phys = <0x0e 0x00>;
                            phy-names = "usb";
                            extcon = <0x0e 0x00>;
                            status = "okay";
                            dr_mode = "otg";
                            phandle = <0x2c>;
                    };
    
  2. Load necessary kernel modules. You can skip this step if you use Armbian OS because necessary modules are already loaded by default (Detailed instructions for sunxi and Ethernet gadget: https://linux-sunxi.org/USB_Gadget/Ethernet)

    modprobe sunxi
    modprobe configfs
    modprobe libcomposite
    modprobe u_ether
    modprobe usb_f_rndis
    
  3. Add sunxi and g_ether to /etc/modules to get them to load on startup. /etc/modules:

    sunxi
    g_ether
    
  4. Configure the g_ether device to start with a stable MAC address. /etc/modprobe.d/g_ether.conf:

    options g_ether host_addr=f6:11:fd:ed:ec:6e
    
  5. Set a static IP address for usb0 on startup with network manager

    /etc/network/interfaces:
      auto usb0
      iface usb0 inet static
          address 192.168.10.2
          netmask 255.255.255.0
    
  6. Boot the PineCube plugging it into a computer

  7. Configure the USB Ethernet device on the computer to be in the same subnet as the PineCube. Example setting:

    network setting: Manual
    address: 192.168.10.5
    netmask: 255.255.255.0
    gateway: 192.168.10.2
    
  8. Done. You can use above methods to stream video through this USB Ethernet connection. Bandwidth and response time is much faster compared to usual network methods.

USB as a Webcam (UVC) gadget

note

This is work in progress.

Goal: Make PineCube behave almost as same as like normal Webcam. When you connect PineCube to a computer it will be shown as a webcam device. No need for an additional set up you can use it straight after plugging the PineCube to a computer. USB-A port is for data transfer between PineCube and computer/phone. Micro-USB port is for power.

Action Plan (by Newton688):

  • Attempt to load the uvc_gadget (usb_f_uvc) or g_webcam
  • Look at this project to see if it can bridge UVC gadget output with the v4l from the OV5650 camera sensor: https://github.com/wlhe/uvc-gadget

Progress report so far (by Disctanger):

Configfs method is going to be used to control OTG port.

  • Additional patch to PineCube device tree disable ehci0 and ohci0, enabling usb_otg device instead and setting dr_mode to otg. If otg is not working for you, try setting dr_mode to peripheral. On Armbian there is no need for disabling ehci0 and ohci0. Device tree can be edited via armbian-config tool on Armbian OS. (armbian-config -> System -> DTC). Example DTC on Armbian:

                    usb@1c19000 {
                            compatible = "allwinner,sun8i-h3-musb";
                            reg = <0x1c19000 0x400>;
                            clocks = <0x03 0x1d>;
                            resets = <0x03 0x11>;
                            interrupts = <0x00 0x47 0x04>;
                            interrupt-names = "mc";
                            phys = <0x0e 0x00>;
                            phy-names = "usb";
                            extcon = <0x0e 0x00>;
                            status = "okay";
                            dr_mode = "otg";
                            phandle = <0x2c>;
                    };
    
  • Load necessary kernel modules:

    modprobe sunxi
    modprobe configfs
    modprobe libcomposite
    
  • Set up camera so that it would capture images in YUYV format (Currently only supported format in UVC gadget). You can adjust resolutions but have to adjust Configfs set up step as well.

    media-ctl --set-v4l2 '"ov5640 1-003c":0[fmt:YUYV8_2X8/640x480@1/30]'
    
  • Clone UVC gadget repo for raspberry pi to your PineCube

    git clone https://github.com/peterbay/uvc-gadget.git
    cd uvc_gadget
    
  • Comment out 1182~1185 lines of uvc-gadget.c file:

    //    if (! uvc_shutdown_requested && ((uvc_dev.dqbuf_count + 1) >= uvc_dev.qbuf_count)) {
    //        return;
    //    }
    
  • Build the source code inside PineCube using make command. It takes only few seconds to build the code.

    make
    gcc -W -Wall -g   -c -o uvc-gadget.o uvc-gadget.c
    gcc -g -o uvc-gadget uvc-gadget.o
    
  • Set up configfs (multi-gadget). You can have the following script as a bash script as well.

    GADGET_PATH=/sys/kernel/config/usb_gadget/pinecube
    
    mkdir $GADGET_PATH
    
    echo 0x1d6b > $GADGET_PATH/idVendor
    echo 0x0104 > $GADGET_PATH/idProduct
    echo 0x0100 > $GADGET_PATH/bcdDevice
    echo 0x0200 > $GADGET_PATH/bcdUSB
    
    echo 0xEF > $GADGET_PATH/bDeviceClass
    echo 0x02 > $GADGET_PATH/bDeviceSubClass
    echo 0x01 > $GADGET_PATH/bDeviceProtocol
    
    mkdir $GADGET_PATH/strings/0x409
    echo 100000000d2386db > $GADGET_PATH/strings/0x409/serialnumber
    echo "Pine64" > $GADGET_PATH/strings/0x409/manufacturer
    echo "PineCube Webcam" > $GADGET_PATH/strings/0x409/product
    mkdir $GADGET_PATH/configs/c.1
    mkdir $GADGET_PATH/configs/c.1/strings/0x409
    echo 500 > $GADGET_PATH/configs/c.1/MaxPower
    echo "UVC" > $GADGET_PATH/configs/c.1/strings/0x409/configuration
    
    mkdir $GADGET_PATH/functions/uvc.usb0
    mkdir $GADGET_PATH/functions/acm.usb0
    echo 512 > $GADGET_PATH/functions/uvc.usb0/streaming_maxpacket
    # cat <<EOF $GADGET_PATH/functions/uvc.usb0/control/processing/default/bmControls
    # 0
    # 0
    # EOF
    
    mkdir -p $GADGET_PATH/functions/uvc.usb0/control/header/h
    ln -s $GADGET_PATH/functions/uvc.usb0/control/header/h $GADGET_PATH/functions/uvc.usb0/control/class/fs/h
    # ln -s $GADGET_PATH/functions/uvc.usb0/control/header/h $GADGET_PATH/functions/uvc.usb0/control/class/hs/h
    # ln -s $GADGET_PATH/functions/uvc.usb0/control/header/h $GADGET_PATH/functions/uvc.usb0/control/class/ss/h
    
    config_frame () {
        FORMAT=$1
        NAME=$2
      WIDTH=$3
      HEIGHT=$4
    
        framedir=$GADGET_PATH/functions/uvc.usb0/streaming/$FORMAT/$NAME/${HEIGHT}p
    
        mkdir -p $framedir
    
        echo $WIDTH > $framedir/wWidth
        echo $HEIGHT > $framedir/wHeight
        echo 333333 > $framedir/dwDefaultFrameInterval
        echo $(($WIDTH * $HEIGHT * 80)) > $framedir/dwMinBitRate
        echo $(($WIDTH * $HEIGHT * 160)) > $framedir/dwMaxBitRate
        echo $(($WIDTH * $HEIGHT * 2)) > $framedir/dwMaxVideoFrameBufferSize
        cat <<EOF > $framedir/dwFrameInterval
    333333
    400000
    666666
    EOF
    
    }
    
    config_frame mjpeg m 640 360
    config_frame mjpeg m 640 480
    config_frame mjpeg m 800 600
    config_frame mjpeg m 1024 768
    config_frame mjpeg m 1280 720
    config_frame mjpeg m 1280 960
    config_frame mjpeg m 1440 1080
    config_frame mjpeg m 1536 864
    config_frame mjpeg m 1600 900
    config_frame mjpeg m 1600 1200
    config_frame mjpeg m 1920 1080
    
    SMALL_WIDTH=480p
    
    mkdir -p $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH
    
    echo 640 > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/wWidth
    echo 480 > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/wHeight
    echo 333333 > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/dwDefaultFrameInterval
    echo $((640 * 480 * 80)) > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/dwMinBitRate
    echo $((640 * 480 * 160)) > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/dwMaxBitRate
    echo $((640 * 480 * 2)) > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/dwMaxVideoFrameBufferSize
    cat <<EOF > $GADGET_PATH/functions/uvc.usb0/streaming/uncompressed/u/$SMALL_WIDTH/dwFrameInterval
    333333
    400000
    666666
    EOF
    
    mkdir $GADGET_PATH/functions/uvc.usb0/streaming/header/h
    cd $GADGET_PATH/functions/uvc.usb0/streaming/header/h
    # ln -s ../../mjpeg/m
    ln -s ../../uncompressed/u
    cd ../../class/fs
    ln -s ../../header/h
    cd ../../class/hs
    ln -s ../../header/h
    cd ../../../../..
    
    ln -s $GADGET_PATH/functions/uvc.usb0 $GADGET_PATH/configs/c.1/uvc.usb0
    ln -s $GADGET_PATH/functions/acm.usb0 $GADGET_PATH/configs/c.1/acm.usb0
    udevadm settle -t 5 ! :
    ls /sys/class/udc > $GADGET_PATH/UDC
    

If above script goes without issues you should be able to see one more additional /dev/video* device.

  • run uvc-gadget. UVC Gadget software links camera of PineCube and UVC gadget (OTG port). “-v” is for video input device - PineCube Camera, “-u” is for output video device UVC device or OTG port, -x shows FPS.

    ./uvc-gadget -u /dev/video1 -v /dev/video0 -x
    
  • Plug the PineCube to your laptop or pc and check if you can see PineCube Webcam.

Known issues

Low Frame rate(3FPS~5FPS). That is because:

  1. At the time of writing this section, streaming_maxpacket value cannot be set to max value (2048 bytes.) It can be set only to 512 bytes. If streaming_maxpacket is set to max (2048) value, UDC cannot be turned on with Invalid Value error.
  2. YUYV (uncompressed) file format is being used to stream the images. Uncompressed images take a lot of USB bandwidth compared to compressed. We can stream more frames, if MJPEG or even H254 (compressed images) would be used. I will be investigating further on how to stream more frames through USB port.