Duo S

Milk-V Duo S is an upgraded model of Duo, featuring an upgraded SG2000 main controller with a larger 512MB memory and expanded IO capabilities. It integrates wireless capabilities with WI-FI 6/BT 5, and comes equipped with a USB 2.0 HOST interface and a 100Mbps Ethernet port for user convenience. Supporting dual cameras (2x MIPI CSI 2-lane) and MIPI video output (MIPI DSI 4-lane), it allows for versatile applications. The device also supports switching between RISC-V and ARM boot through a switch. With enhanced functionality, Duo S is better suited for a variety of scenarios with more complex project development requirements.

Introduction of SG2000

SG2000 is a high-performance, low-power chip designed for various product fields such as edge intelligent surveillance IP cameras, local facial recognition attendance machines, and smart home devices. It integrates H.264/H.265 video compression and decoding and ISP capabilities. It supports various image enhancement and correction algorithms like HDR wide dynamic range, 3D noise reduction, defogging, and lens distortion correction, providing customers with professional-grade video image quality.

The chip also integrates an in-house TPU, delivering approximately 0.5TOPS of computing power under INT8 operations. The specially designed TPU scheduling engine efficiently provides high-bandwidth data flow for tensor processing unit cores. It also offers users a powerful deep learning model compiler and software SDK development kit. Mainstream deep learning frameworks such as Caffe, Pytorch, ONNX, MXNet, and TensorFlow (Lite) can be easily ported to this platform.

SG2000 Public Preliminary Datasheet

We have open sourced the Public Preliminary Datasheet and TRM of SG2000 to GitHub. please check it out.

Buy the SG2000 Chips

Milk-V is the Authorised Global Distributor of the SG2000 chips. You can buy samples of the SG2000 chip from our distributor online store directly. For volume order, please contact Milk-V Sales Team for the qoutation.

Getting Started

Installing the system

• Boot from SD card

  Please refer to the Start Up section.

• Boot from eMMC

  Please refer to: eMMC version firmware burning section.

USB Network Usage

Please refer to the Setup section.

DuoS GPIO Pinout

GPIO pin mapping

GROUP	ADDR	PORT	CHIP	NUM	NAME	START
gpio0	gpio@03020000	porta	gpiochip0	480-511	XGPIOA	480 - XGPIOA[0]
gpio1	gpio@03021000	portb	gpiochip1	448-479	XGPIOB	448 - XGPIOB[0]
gpio2	gpio@03022000	portc	gpiochip2	416-447	XGPIOC	416 - XGPIOC[0]
gpio3	gpio@03023000	portd	gpiochip3	384-415
gpio4	gpio@05021000	porte	gpiochip4	352-383	PWR_GPIO	352 - PWR_GPIO[0]

Header J3

GPIO on Header J3 use 3.3V logic levels.

SPI	PWM	I2C	UART	NUM	SG2000	NAME	PIN	PIN	NAME	SG2000	NUM	UART	PWM	SPI	JTAG
						3V3	1	2	VSYS(5V)
	PWM3	I2C4_SCL		468	XGPIOB[20]	B20	3	4	VSYS(5V)
		I2C4_SDA		469	XGPIOB[21]	B21	5	6	GND
		I2C1_SCL		466	XGPIOB[18]	B18	7	8	A16	XGPIOA[16]	496	UART0_TX/UART1_TX	PWM4
						GND*	9	10	A17	XGPIOA[17]	497	UART0_RX/UART1_RX	PWM5
	PWM1	I2C1_SDA	UART2_TX	459	XGPIOB[11]	B11	11	12	B19	XGPIOB[19]	467	UART2_TX	PWM2
	PWM2	I2C1_SCL	UART2_RX	460	XGPIOB[12]	B12	13	14	GND
			UART2_RX	470	XGPIOB[22]	B22	15	16	A20	XGPIOA[20]	500				JTAG_TRST
						3V3	17	18	A19	XGPIOA[19]	499	UART1_TX/UART1_RTS	PWM7		JTAG_TMS
SPI3_SDO	PWM3	I2C2_SCL		461	XGPIOB[13]	B13	19	20	GND
SPI3_SDI		I2C2_SDA		462	XGPIOB[14]	B14	21	22	A18	XGPIOA[18]	498	UART1_RX/UART1_CTS	PWM6		JTAG_TCK
SPI3_SCK			UART2_TX	463	XGPIOB[15]	B15	23	24	B16	XGPIOB[16]	464	UART2_RX		SPI3_CS
						GND	25	26	A28	XGPIOA[28]	508	UART2_TX/UART1_TX

GND*: Pin 9 is a low-level GPIO in the V1.1 version of the hardware, and is GND in the V1.2 version and later.

NOTE: The I2C on the CSI camera connector J2 is I2C2, so when using the CSI camera on J2, I2C2 in the J3 pin header is not available.

Header J4

GPIO on Header J4 use 1.8V logic levels.

PWM	I2C	UART	MIPI DSI	NUM	SG2000	NAME	PIN	PIN	NAME	SG2000	NUM	MIPI DSI
						VSYS(5V)	52	51	AUDIO_OUT_R
PWM12	I2C4_SCL	UART3_TX		449	XGPIOB[1]	B1	50	49	AUDIO_OUT_L
PWM13	I2C4_SDA	UART3_RX		450	XGPIOB[2]	B2	48	47	AUDIO_IN_R
				451	XGPIOB[3]	B3	46	45	AUDIO_IN_L
PWM10	I2C2_SDA		LCD_RST	354	PWR_GPIO[2]	E2	44	43	3V3
PWM9	I2C2_SCL	UART2_RX	LCD_PWR_CT	353	PWR_GPIO[1]	E1	42	41	C18	XGPIOC[18]	434	MIPI_TX_3N
PWM8		UART2_TX	LCD_PWM	352	PWR_GPIO[0]	E0	40	39	C19	XGPIOC[19]	435	MIPI_TX_3P
						GND	38	37	GND
			MIPI_TX_2N	436	XGPIOC[20]	C20	36	35	C16	XGPIOC[16]	432	MIPI_TX_CN
			MIPI_TX_2P	437	XGPIOC[21]	C21	34	33	C17	XGPIOC[17]	433	MIPI_TX_CP
						GND	32	31	GND
			MIPI_TX_1N	430	XGPIOC[14]	C14	30	29	C12	XGPIOC[12]	428	MIPI_TX_0N
			MIPI_TX_1P	431	XGPIOC[15]	C15	28	27	C13	XGPIOC[13]	429	MIPI_TX_0P

Blue LED PIN

NAME	SG2000	NUM
LED	XGPIOA[29]	509

Camera interface

DuoS has two CSI camera connectors:

• J1 is a 16 PIN 0.5mm pitch connector compatible with Duo and Duo256M cameras, and can directly use the CAM-GC2083 camera.
• J2 is a 15-pin 1.0mm pitch connector compatible with the Raspberry Pi camera interface. It currently supports the OV5647 camera used on the Raspberry Pi.

Note that the I2C used by the J1 interface is I2C3, and the I2C used by the J2 interface is I2C2. Please check the pin multiplexing configuration when using it.

J1 Connector FPC Definition

J1	Description
1	GND
2	MIPI0_DN0
3	MIPI0_DP0
4	GND
5	MIPI0_DN1
6	MIPI0_DP1
7	GND
8	MIPI0_CKN
9	MIPI0_CKP
10	GND
11	SENSOR_RSTN0 (1.8V)
12	SENSOR_CLK0 (1.8V)
13	I2C3_SCL (1.8V)
14	I2C3_SDA (1.8V)
15
16	3V3

J2 Connector FPC Definition

J2	Description
1	3V3
2	I2C2_SDA (3.3V)
3	I2C2_SCL (3.3V)
4	SENSOR_CLK1 (3.3V)
5	SENSOR_RSTN1 (3.3V)
6	GND
7	MIPI0_DP5 (CAM1_CP)
8	MIPI0_DN5 (CAM1_CN)
9	GND
10	MIPI0_DP4 (CAM1_DP1)
11	MIPI0_DN4 (CAM1_DN1)
12	GND
13	MIPI0_DP3 (CAM1_DP0)
14	MIPI0_DN3 (CAM1_DN0)
15	GND

POE Header

POE Pin	Description
1	VB-
2	VB+
3	VA-
4	VA+

DuoS User Guide

RISC-V and ARM switching

The large core of DuoS can choose to use RISC-V or ARM processor, which can be set through the switch on the board. If you find that DuoS cannot start normally during use, please first check whether the switch is consistent with the firmware used.

If the debug serial port is connected, you can see in the first line of the boot log that starting with C means starting from the RISC-V core, and starting with B means starting from the ARM core.

• RISC-V:

  C.SCS/0/0.C.SCS/0/0.WD.URPL.USBI.USBW
• ARM:

  B.SCS/0/0.WD.URPL.B.SCS/0/0.WD.URPL.USBI.USBW

Usage of USB Type A interface

The USB functions of the DuoS USB Type A interface and Type C interface are optional and cannot be used at the same time. The default firmware is configured with the USB network port (USB-NCM) function of the Type C port. If you need to switch to the USB 2.0 HOST port of the Type A port for use with USB flash drives and other devices, you need to execute the following command:

ln -sf /mnt/system/usb-host.sh /mnt/system/usb.sh
sync

Then execute the reboot command or power on again to make it take effect.

For example, after connecting a USB flash drive to the USB A port, you can use ls /dev/sd* to check whether the device is detected.

Mount it to the system to view the contents of the USB flash drive (take /dev/sda1 as an example):

mkdir /mnt/udisk
mount /dev/sda1 /mnt/udisk

Check whether the contents of the /mnt/udisk directory are as expected:

ls /mnt/udisk

Command to uninstall USB flash drive:

umount /mnt/udisk

When you want to restore the USB network (USB-NCM) function of the Type C port, execute:

rm /mnt/system/usb.sh
ln -sf /mnt/system/usb-ncm.sh /mnt/system/usb.sh
sync

Then execute the reboot command or power on again to make it take effect.

совет

DuoS has an onboard Ethernet interface, so the USB network port (USB-NCM) of the Type C port can be used without switching to the USB 2.0 Host function of the A port.

Fixed ethernet port MAC address

If you need to assign a fixed MAC address to the Ethernet port of DuoS, please execute the following command:

совет

Replace the MAC address in the command with the MAC address you want to set, and please note that MAC addresses of different devices within the same network segment must not be duplicated

echo "pre-up ifconfig eth0 hw ether 78:01:B3:FC:E8:55" >> /etc/network/interfaces && sync

then reboot the board.

UART Serial Console

DuoS has a reserved UART debug serial port, which can be used to view the system startup log, or to log in to the console after the system starts and execute some terminal commands.

USB-TTL Serial Cable

The serial port level of Duo series is 3.3V.

The pin definitions of common USB to TTL serial cables are as follows:

Connection

Connect the USB to TTL serial cable as shown below, leaving the red wire unconnected.

Milk-V DouS	<--->	USB to TTL
GND (pin 6)	<--->	Black wire
TX (pin 8)	<--->	White wire
RX (pin 10)	<--->	Green wire

The default serial port parameters of DuoS are as follows:

baudrate: 115200
data bit: 8
stop bit: 1
parity  : none
flow control: none

WIFI configuration

Method 1

Edit the following file and replace ssid and psk with the WIFI account and password to be connected:

/etc/wpa_supplicant.conf

ctrl_interface=/var/run/wpa_supplicant
ap_scan=1
update_config=1

network={
  ssid="wifi_test"
  psk="12345678"
  key_mgmt=WPA-PSK
}

Then execute the following command:

wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant.conf

You can connect to WIFI. After connecting, you can view the assigned IP address through the ifconfig or ip a command.

If you need to automatically connect to the WIFI when booting, you can put the following command in the /mnt/system/auto.sh file.

interface="wlan0"
max_attempts=100
attempt=0
log_file="/var/log/auto.sh.log"

# Continuously attempt to detect if the interface exists, up to $max_attempts times
echo "start auto.sh" > "$log_file"
while [ $attempt -lt $max_attempts ]; do
    # Check if the wlan0 interface exists
    ip link show "$interface" > /dev/null 2>&1
    if [ $? -eq 0 ]; then
        echo "$(date +'%Y-%m-%d %H:%M:%S') $interface interface exists, starting wpa_supplicant..." >> "$log_file"
        wpa_supplicant -B -i "$interface" -c /etc/wpa_supplicant.conf >> "$log_file"
        break  # Exit the loop if the interface is found
    else
        echo "$(date +'%Y-%m-%d %H:%M:%S') $interface interface not found, waiting..." >> "$log_file"
        sleep 1  # Wait for 1 second before checking again
        attempt=$((attempt + 1))  # Increment the attempt counter
    fi
done

# If the maximum number of attempts is reached and the interface still not found, output an error message
if [ $attempt -eq $max_attempts ]; then
    echo "$(date +'%Y-%m-%d %H:%M:%S') Interface $interface not found after $max_attempts attempts" >> "$log_file"
fi

Fixed WIFI MAC address

DuoS WIFI MAC address is randomly assigned. If you need to assign a fixed MAC address to the WIFI of DuoS, please execute the following command::

совет

Replace the MAC address in the command with the MAC address you want to set, and please note that MAC addresses of different devices within the same network segment must not be duplicated

echo "MAC_ADDR=11:22:33:44:55:66" > /mnt/system/firmware/aic8800/rwnx_settings.ini && sync

then reboot the board.

eMMC version firmware burning

The DuoS eMMC version does not have firmware burned and needs to be burned using a PC through the USB interface.

совет

Use the USB burning tool under Windows to support eMMC. The firmware version is V1.1.3 or latest version.

Burning in Windows

1. Install driver

   Download the USB driver installation tool: CviUsbDownloadInstallDriver.zip. After downloading, unzip and install.

2. Download burning tool

   Download the command line burning tool under Windows CviBurn_v2.0_cli_windows.zip, unzip it after downloading.

3. Download firmware

   Download the latest version of DuoS eMMC firmware, currently milkv-duos-emmc-v1.1.3-2024-0930.zip, you can create a new rom folder in the burning tool CviBurn_v2.0_cli_windows directory, and extract the downloaded eMMC firmware compressed package to rom directory, the directory structure of the burning tool is as follows:

   └───CviBurn_v2.0_cli_windows
    │   cv_dl_magic.bin
    │   usb_dl.exe
    └───rom
        │   boot.emmc
        │   fip.bin
        │   partition_emmc.xml
        │   rootfs_ext4.emmc
        |   ...

   In the Windows terminal, execute the burning command in the CviBurn_v2.0_cli_windows directory:

   .\usb_dl.exe -s linux -c cv181x -i .\rom

   *You can also put the firmware in other directories and specify the corresponding directory through the -i parameter in the command. *

   Displays message waiting for USB connection:

   

   Press and hold the recovery button on the DuoS, and then connect the DuoS and PC using a Type-C data cable.

   warning

   Before doing this step, remove SD Card first!!

   

   Release the recovery button, DuoS will power on and enter the burning mode, and the PC will display the burning progress in real time:

   [INFO] Waiting for USB device connection: ---
   [INFO] found usb device vid=0x3346 pid=0x1000
   [INFO] downloading file: .\rom\boot.emmc
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 3384664/213100824(1%)
   [INFO] downloading file: .\rom\rootfs_ext4.emmc
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 20161944/213100824(9%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 36939224/213100824(17%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 53716504/213100824(25%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 70493784/213100824(33%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 87271064/213100824(40%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 104048344/213100824(48%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 120825624/213100824(56%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 137602904/213100824(64%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 154380184/213100824(72%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 171157464/213100824(80%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 187934744/213100824(88%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 204712024/213100824(96%)
   [INFO] CVI_USB_PROGRAM
   [INFO] updated size: 213100696/213100824(99%)
   [INFO] USB download complete

   After the burning is completed, the DuoS will automatically restart. After booting, you will see the blue LED on the DuoS flashing, indicating that the system has started normally and the burning is successful.

eMMC Erase

If you need to restore the eMMC to its initial state, please refer to the following command to clear the eMMC data (please back up important files in the eMMC in advance):

• Unlock readonly

  echo 0 > /sys/block/mmcblk0boot0/force_ro
  echo 0 > /sys/block/mmcblk0boot1/force_ro
• Erase

  dd if=/dev/zero of=/dev/mmcblk0boot0 bs=1M count=4
  dd if=/dev/zero of=/dev/mmcblk0boot1 bs=1M count=4

Hardware Docs

Others

https://github.com/milkv-duo/duo-files/tree/main/duo-s