Bluetooth LE SoC Board (BTU)

The Tuya Sandwich Bluetooth LE SoC board (BTU) has Tuya’s BTU Bluetooth Low Energy (LE) network module as a microcontroller, which is designed to help you easily prototype your IoT ideas. It can work with other circuit boards to implement specific features.

Applications

• This development board applies to a wide range of prototypes implemented with Tuya’s no-code or TuyaOS solutions.
• 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 Bluetooth-based control system works

Components

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

I/O port and pin description

• 1: Jumper switches (P9 and P8), used to change the mode of the user port. Placing a jumper cap on PB1-TXD and PB7-RXD enables the module’s pin to connect to the TX and RX pins. Placing a jumper cap on PB1-U_RXD and PB7-U_TXD enables the module’s pins to connect to the U2 chip so that the user port can communicate with the module through the micro-USB port.

• 2: Micro-USB (P2): Inputs 5V DC voltage and provides one extended serial port.

• 3: DC-005 (P1): Inputs 12V DC voltage.

• 4: Button (S2): Connected to the PA0 pin on the module. When the button is pressed, the low level is output. When the button is released, the high level is output.

• 5: Serial port (P3): Used to flash firmware to the BTU module.

• 6: Button (S1): Connected to the RST pin on the module. When the button is pressed, the low level is output, and the module is reset.

• Pin description

  No.	Symbol	Description
  1	NC	Leave it floating.
  2	NC	Leave it floating.
  3	RST	Reset the module, low-voltage reset.
  4	3V3	3.3V power pin.
  5	5V	5V power pin.
  6	GND	Ground pin.
  7	GND	Ground pin.
  8	VIN	12V power pin.
  9	PB6	GPIOB_6 of the module, which can be reused as the ADC.
  10	NC	Leave it floating.
  11	NC	Leave it floating.
  12	NC	Leave it floating.
  13	NC	Leave it floating.
  14	NC	Leave it floating.
  15	TX	Use a jumper cap to switch to the GPIOB_1 pin of the module. This pin can be reused as the TXD of the user port.
  16	RX	Use a jumper cap to switch to the GPIOB_7 pin of the module. This pin can be reused as the RXD of the user port.
  17	PA1	GPIOA_1 of the module.
  18	PC2	GPIOC_2 of the module, which can be reused as the PWM.
  19	PD3	GPIOD_3 of the module.
  20	PC3	GPIOC_3 of the module, which can be reused as the PWM.
  21	PB4	GPIOB_4 of the module, which can be reused as the PWM.
  22	PD4	GPIOD_4 of the module.
  23	PA7	GPIOA_7 of the module. It defaults to the SWS pin, used for firmware flashing.
  24	PB5	GPIOB_5 of the module, which can be reused as the PWM.
  25	PC4	GPIOC_4 of the module, which can be reused as the ADC.
  26	PD2	GPIOD_2 of the module, which can be reused as the PWM.
  27	PA0	GPIOA_0 of the module.
  28	PD7	GPIOD_7 of the module.
  29	GND	Ground pin.
  30	NC	Leave it floating.
  31	PC0	GPIOC_0 of the module.
  32	PC1	GPIOC_1 of the module.

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.
  5V	5V/1A
  3V3	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 5V

  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 the 3V3 pin.

• Characteristics of the output voltage of 3V3 pin

  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 the 5V pin.

Schematic diagram and PCB

• The schematic diagram of the board:

  

• The PCB board:

  

How USB-to-serial works

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

  Pin connection description

  Silkscreen	P9	P8
  Pins on module	PB1	PB7
  Pins on board	TX	RX
  USB-to-serial chip	USB-RXD	USB-TXD

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

  

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

  

• The 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.

  

USB-to-serial chip driver

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

• For Windows
• For Linux
• For macOS

Things to note

• The board has a built-in power supply port and circuit, so the additional power board is not necessary.