Wi-Fi and Bluetooth LE SoC Board (CBU)

The Tuya Sandwich Wi-Fi and Bluetooth LE combo SoC has Tuya’s CBU network module as a microcontroller, which is designed to help you easily prototype your IoT ideas. It can work with functional boards or circuit boards to implement specific features.

Applications

• This development board applies to a wide range of prototypes implemented with Tuya’s no-code solutions, such as sockets, power strips, switches, and lights.
• Develop with the board to build your IoT projects easily and fast.
• You can use this board for different development purposes.
  • Embedded program development and debugging
  • App development and debugging
  • Creating connected devices that can be controlled with a mobile phone
  • Getting started with IoT development and learning how the Wi-Fi-based control system works

Components

The development board is integrated with Tuya’s proprietary high-performance Wi-Fi and Bluetooth LE combo module. It has on-board buttons, LED, GPIOs, and a USB-to-serial chip. For more information, see the CBU Module Datasheet.

I/O port and pin description

• 1: LED indicator (LED2): When P16 outputs high, the LED is on.

• 2: Button (SW1): When the button is pressed, P28 outputs low. When the button is released, it outputs high.

• 3: DC-005 (CN5): Inputs 12V DC voltage.

• 4: Micro-USB (CN1): Inputs 5V DC voltage and provides two extended serial ports.

• 5: Button (SW1): Module’s enable pin that is active low. When the button is pressed, the pin outputs low.

• Pin description

  No.	Pin name	Function
  1	NC	Leave it floating.
  2	NC	Leave it floating.
  3	CEN	Module’s enable pin that is active low.
  4	VCC	3.3V power pin.
  5	VDD	5V power pin.
  6	GND	Ground pin.
  7	GND	Ground pin.
  8	VIN	12V power pin.
  9	ADC	P23 on the module. It can be reused as ADC.
  10	NC	Leave it floating.
  11	NC	Leave it floating.
  12	NC	Leave it floating.
  13	TXD2	You can use a jumper cap to switch to UART_TX2 on the module. UART_TX2 supports log printing, corresponding to P0 on the IC. You can also use a jumper cap to leave TXD2 floating.
  14	RXD2	You can use a jumper cap to switch to UART_RX2 on the module. UART_RX2 corresponds to P1 on the IC. Do not use P1. You can also use a jumper cap to leave RXD2 floating.
  15	RXD1	You can use a jumper cap to switch to UART_RX1 on the module. UART_RX1 receives user data, corresponding to P10 on the IC. You can also use a jumper cap to leave RXD1 floating.
  16	TXD1	You can use a jumper cap to switch to UART_TX1 on the module. UART_TX1 sends user data, corresponding to P11 on the IC. You can also use a jumper cap to leave TXD1 floating.
  17	NC	Leave it floating.
  18	P24	P24 on the module. A normal GPIO that can be reused as hardware PWM4.
  19	P16	P16 on the module. A normal GPIO that can be reused as SPI_MOSI.
  20	P26	P26 on the module. A normal GPIO that can be reused as hardware PWM5.
  21	P06	P6 on the module. A normal GPIO that can be reused as hardware PWM0.
  22	P28	P28 on the module. A normal GPIO.
  23	P09	P9 on the module. A normal GPIO that can be reused as hardware PWM3.
  24	P07	P7 on the module. A normal GPIO that can be reused as hardware PWM1.
  25	P15	P15 on the module. A normal GPIO that can be reused as SPI_CS.
  26	P08	P8 on the module. A normal GPIO that can be reused as hardware PWM2.
  27	P17	P17 on the module. A normal GPIO that can be reused as SPI_MISO.
  28	P14	P14 on the module. A normal GPIO that can be reused as SPI_SCK.
  29	GND	Ground pin.
  30	NC	Leave it floating.
  31	P22	P22 on the module. A normal GPIO.
  32	P20	P20 on the module. A normal GPIO.

Load-carrying capacity

• When DC-005 inputs 12V DC voltage, the board can supply power to external components.

  Power pin	Rated voltage/current
  VIN	Depends on the input current of the adapter connected to the DC-005 terminal.
  VDD	5V/1A
  VCC	3.3V/0.6A

  This board outputs rated power of 5W, which cannot support the long-time simultaneous output of 5V/1A and 3.3V/0.6A.

• Characteristics of the output voltage of VDD

  Output current	0A	0.25A	0.5A	0.75A	1A	1.25A
  Output voltage	5.01V	5.00V	4.99V	4.98V	4.98V	4.97V

  We tested the voltage under the condition that there is no output voltage on VCC.

• Characteristics of output voltage

  Output current	0A	0.15A	0.3A	0.45A	0.6A	0.75A
  Output voltage	3.34V	3.36V	3.37V	3.37V	3.38V	3.38V

  We tested the voltage under the condition that there is no output voltage on VDD.

Schematic diagram and PCB

• The schematic diagram of the board:

  

• The PCB board:

  

How USB-to-serial chip works

• The board has a built-in USB-to-serial chip. The single-channel USB port can provide two extended serial ports. You can use a jumper cap to allow the 2-channel serial port on the module to connect to the USB-to-serial chip. Pin connection description

  Silkscreen of pin header	CN9	CN8	CN4	CN5
  Pins on module	UART_RX2	UART_TX2	UART_TX1	UART_RX1
  Pins on board	RXD2	TXD2	TXD1	RXD1
  Pins on USB-to-serial chip	USB-TX1	USB-RX1	USB-RX2	USB-TX2

• The serial port is left floating and not connected to the pins on the USB-to-serial chip or the board. The four headers are open without jumper caps.
  

• The two serial ports on the module are connected to the USB-to-serial chip. The RXD2, TXD2, TXD1, and RXD1 on the board are left floating. Put the jumper caps as shown below.
  

• The two serial ports on the module are connected to the pins on the board. The pins on the USB-to-serial chip are left floating. Put the jumper caps as shown below.
  

• Connect UART1 (user serial) to the pins on the board, UART2 (log printing) to the USB-TX1 and USB-RX1. Put the jumper caps as shown below.
  

• Connect UART1 (user serial) to USB-TX2 and USB-RX2, UART2 (log printing) to pins on the board. Put the jumper caps as shown below.
  

Connection for flashing

For flashing license and firmware, connect pins following the table and figure shown below.

USB-to-serial chip driver

Download the USB-to-serial chip driver for your operating system.

• For Windows
• For Linux

Things to note

• The board has a built-in power supply port and circuit, so the additional power board is not necessary.
• You can connect the USB port (5V) or DC005 port (12V) to a power supply. Note that the DC005 port does not support input voltage less than 7V.
• If you connect the board to a power board, do not use the DC005 port for voltage input.