Bluetooth LE-BG24

This topic describes the basics of the chip platform used in TuyaOS development. For more information, visit Tuya Developer Forum.

Hardware environment

Datasheet

• Method 1: After integrating the Bluetooth Sub-Device Development Framework, you can get the datasheet and reference manual in the vendor\bg24_ble\documents\ path.
• Method 2: Visit the official website of Silicon Labs and get the latest information in the Documentation Center.

Development board

• Tuya BS24-U Module Datasheet

• Tuya BS24-U-IPEX Module Datasheet

• The following figure shows BS24-U-EVB:

  

• The following figure shows the development board from the chip vendor:

  

Peripherals

Peripherals and corresponding GPIOs

GPIO

The SDK defaults to using the EFR32BG24A020IM40 chip model. All peripheral descriptions below are based on this chip. To change to a 48-pin package, define BOARD_GPIO_MAX to 48 in the app_config.h file.

To operate a specific I/O in TuyaOS, you need to specify its pin number in the input parameter. For the BG24 series chip platform, the table below shows the mapping between GPIO numbers and physical I/O pins:

QFN40

GPIO No.	Pin	GPIO No.	Pin
TUYA_GPIO_NUM_1	PC00	TUYA_GPIO_NUM_2	PC01
TUYA_GPIO_NUM_3	PC02	TUYA_GPIO_NUM_4	PC03
TUYA_GPIO_NUM_5	PC04	TUYA_GPIO_NUM_6	PC05
TUYA_GPIO_NUM_7	PC06	TUYA_GPIO_NUM_8	PC07
TUYA_GPIO_NUM_16	PB04	TUYA_GPIO_NUM_17	PB03
TUYA_GPIO_NUM_18	PB02	TUYA_GPIO_NUM_19	PB01
TUYA_GPIO_NUM_20	PB00	TUYA_GPIO_NUM_21	PA00
TUYA_GPIO_NUM_24	PA03	TUYA_GPIO_NUM_25	PA04
TUYA_GPIO_NUM_26	PA05	TUYA_GPIO_NUM_27	PA06
TUYA_GPIO_NUM_28	PA07	TUYA_GPIO_NUM_29	PA08
TUYA_GPIO_NUM_37	PD03	TUYA_GPIO_NUM_38	PD02
TUYA_GPIO_NUM_39	PD01	TUYA_GPIO_NUM_40	PD00

QFN48

GPIO No.	Pin	GPIO No.	Pin
TUYA_GPIO_NUM_1	PC00	TUYA_GPIO_NUM_2	PC01
TUYA_GPIO_NUM_3	PC02	TUYA_GPIO_NUM_4	PC03
TUYA_GPIO_NUM_5	PC04	TUYA_GPIO_NUM_6	PC05
TUYA_GPIO_NUM_7	PC06	TUYA_GPIO_NUM_8	PC07
TUYA_GPIO_NUM_9	PC08	TUYA_GPIO_NUM_10	PC09
TUYA_GPIO_NUM_18	PB05	TUYA_GPIO_NUM_19	PB04
TUYA_GPIO_NUM_20	PB03	TUYA_GPIO_NUM_21	PB02
TUYA_GPIO_NUM_22	PB01	TUYA_GPIO_NUM_23	PB00
TUYA_GPIO_NUM_26	PA00	TUYA_GPIO_NUM_27	PA01
TUYA_GPIO_NUM_28	PA02	TUYA_GPIO_NUM_29	PA03
TUYA_GPIO_NUM_30	PA04	TUYA_GPIO_NUM_31	PA05
TUYA_GPIO_NUM_32	PA06	TUYA_GPIO_NUM_33	PA07
TUYA_GPIO_NUM_34	PA08	TUYA_GPIO_NUM_35	PA09
TUYA_GPIO_NUM_43	PD05	TUYA_GPIO_NUM_44	PD04
TUYA_GPIO_NUM_45	PD03	TUYA_GPIO_NUM_46	PD02
TUYA_GPIO_NUM_47	PD01	TUYA_GPIO_NUM_48	PD00

PWM

By default, there are five PWM channels, occupying three channels of Timer0 and two of Timer1. Both Timer0 and Timer1 are 32-bit timers.

Channel	Pin
0	PC01
1	PC02
2	PA04
3	PA05
4	PA06

UART

The system defaults to using two UART groups, with UART0 mapped to USART0 and UART1 mapped to EUSART0. The EUSART (only two groups available) can be multiplexed as SPI, UART, or card reader interfaces. Here, only its UART functionality is utilized.

UART	Feature	Pin	Remarks
UART0	TX	PD03	Authorization and testing
UART0	RX	PD02	-
UART1	TX	PA00	Demo not used
UART1	RX	PB00	-

SPI

SPI	Feature	Pin
SPI0	CS	PC00
SPI0	CLK	PC03
SPI0	SDI	PA00
SPI0	SDO	PB00

ADC

The chip supports 16 input channels, each of which can be configured as positive input (posInput) and negative input (negInput) modes. By default, negInput is connected to ground (GND, suitable for single-ended sampling). All I/Os of PAx, PBx, PCx, and PDx can be mapped to the input ports of IADC. They can be configured as single-channel sampling or multi-channel auto-scanning sampling mode.

By default, the SDK only supports one ADC to optimize resource usage. For additional channels, you can configure them by yourself.

Channel	Pin
0	PB02

I2C

The chip has two I2C interfaces, supporting 100 kHz, 400 kHz, and 1 MHz. To display SDK information (TuyaOS demo), the OLED is pre-initialized. I2C0 is used by default.

I2C	Feature	Pin
IIC0	SCL	PB02
IIC0	SDA	PB01

Key control

PB04:

• Press the key to wake up the device.
• Press and hold the key for three seconds to factory reset the device.

Startup time detection pin

PA08: Used for power-on startup time detection. It is set to a high level after entering the main function.

Software environment

• Make sure the make command line tool has been installed in the environment, or search and install make, configure the environment variables, and compile again.

• The SDK includes the pre-packaged Commander CLI tool (for flashing and log output), located at vendor\bg24_ble\toolchain\software\commander.

• The toolchain is already integrated into the SDK, so there is no need to download it again.

Develop software

Select chip type

The default chip model used by the SDK is EFR32BG24A020IM40. If you need to replace it with a chip model in a 48-pin package, you must define BOARD_GPIO_MAX as 48 in the app_config.h file.

SDK footprint

Flash memory allocation: The allocated application region is 352 KB, with approximately 270 KB actually utilized.

Remarks

• For more information on setting up the onboard GPIOs, be sure to refer to the documentation.

• For flash memory allocation settings, refer to the document bg24_flash.md: vendor\bg24_ble\documents.

Flash firmware

Both firmware flashing and device logging are performed through the J-Link SWD interface.

1. Flash and erase: Click in the order shown below to perform the flash and erase operations.

   

2. Logging system (RTT): Click in the order shown below to view the software running log and get debugging information. Alternatively, you can launch and run the J-Link RTT Viewer software.

   

Platform features

Flash partition

For more information, refer to the document bg24_flash.md: vendor\bg24_ble\documents.

Feature name	Details	Address	Size	Remarks
bootloader (32 KB)	Bootloader	0x0800 0000-0x0800 7FFF	32 KB	The boot partition
Application firmware area (496 KB)	Application_Firmware	0x0800 8000-0x0808 3FFF	496 KB	Application code area
Update area (392 KB)	OTA backup	0x0808 4000-0x0808 7FFF	16 KB	Incremental restoration backup area
	OTA patch (Firmware)	0x0808 8000-0x080D FFFF	352 KB	See note 1
	OTA manage info	0x080E 0000-0x080E 3FFF	16 KB	OTA management information
	OTA breakpoint info	0x080E 4000-0x080E 5FFF	8 KB	Resumable download information
Reserved area 1 (24 KB)	Reserved 1 data	0x080E 6000-0x080E BFFF	24 KB	Reserved area 1
Bulk data area (16 KB)	Bulk data	0x080E C000-0x080E FFFF	16 KB	Bulk data storage area
Authorization data (32 KB)	Auth data	0x080F 0000-0x080F 7FFF	32 KB	See note 2
NVM3 area (24 KB)	Bluetooth core Nvm3	0x080F 8000-0x080F EFFF	24 KB	Original protocol stack storage area
Reserved area 2 (8 KB)	Reserved 2 data	0x080F F000-0x080F FFFF	8 KB	Reserved area 2

Power consumption

Test method

1. Disconnect all external cables except for the serial cable connected to the host. You can connect a USB to TTL converter to the serial port on the board. Connect the TX and RX of the USB serial port to PD02 and PD03, respectively.

2. Connect to an ammeter that can provide 3.3V of power. Connect the positive pole of the power supply to the VCC pin, and the negative pole to the GND on the board.

3. You can measure the power consumption in different modes using power management in the host software.

Power consumption

• Broadcasting at 100 ms intervals results in approximately 2.5 mA typical power consumption.

  

• Low-power broadcasting at 100 ms intervals consumes approximately 320 μA in EM2 mode.

  

• By default, 1-second interval broadcasting consumes approximately 35 μA.

  

• Without broadcasting, the EM2 power consumption is approximately 3.2 μA. Turn off all peripherals and advertising, maintain RTC and RAM data, and enable GPIO wake-up.