Bluetooth LE–BK3633

Last Updated on : 2024-07-26 10:26:07download

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

Hardware environment

Datasheet

The datasheet can be found in hardware\BK3633\chip_manual\BK3633_Datasheet_V1.5.pdf.
Alternatively, check the Beken website for the latest information.

Development board

Development board from chip vendor

Peripherals

GPIO

Three specification options are provided: 32 pins, 40 pins, and 48 pins. There are up to 32 GPIO pins that can be configured as input or output. GPIO pins can be reused for another feature. For more information, see 2 Pin Information and 3.2 GPIO in .\hardware\BK3633\chip_manual. The table below shows the mapping between pin numbers and BK3633 pin names.

TUYA_GPIO_NUM definition	Pin
TUYA_GPIO_NUM_0 to TUYA_GPIO_NUM_07	P00 to P07
TUYA_GPIO_NUM_10 to TUYA_GPIO_NUM_17	P10 to P17
TUYA_GPIO_NUM_20 to TUYA_GPIO_NUM_27	P20 to P27
TUYA_GPIO_NUM_30 to TUYA_GPIO_NUM_37	P30 to P37

UART

The BK3633 platform has two non-configurable UART interfaces: UART0 and UART2. The table below shows the default pin definitions.

UART	Feature	Pin	Description
UART0	TX	P00	Used to flash firmware and license and connect to a host for testing. The baud rate defaults to 9600.
UART0	RX	P01	-
UART2	TX	P16	Used to print logs. The baud rate defaults to 115200.
UART2	RX	P17	-

SPI

The BK3633 platform has one SPI interface, supporting controller and peripheral modes, operating at speeds up to 32 MHz, with a frequency range of 126 kHz to 32 MHz.

The SPI controller interface is used by default. You can connect the MISO and MOSI signals together (that is, short the P06 and P05) to perform a loopback test. The default pin definitions:

SPI Feature Pin

SPI0 CS P07

SPI0 CLK P04

SPI0 MOSI P05

SPI0 MISO P06
I2C

The BK3633 platform has one I2C interface, supporting 100 kHz and 400 kHz. The SDK configuration only supports I2C controller mode and 7-bit addresses. To display SDK information (TuyaOS demo), the OLED is pre-initialized. I2C0 is used by default.

I2C Feature Pin

I2C0 SCL P02

I2C0 SDA P03
PWM

The BK3633 platform supports 6-channel PWM output, channels 0 to 5. The SDK uses a 16 MHz main crystal oscillator as the default clock, operating within a frequency range of 1 Hz to 8 MHz. The table below lists the mapping between the channel and the default pin.

Channel Pin

0 P10

1 P11

2 P12

3 P13

4 P14

5 P15
ADC

10-bit ADC, eight channels (five external test channels and three internal signal channels), supporting single and continuous modes. The external channel supports a voltage range of 0 to 1.05V with an accuracy of ±50 mV. The table below lists the mapping between the channel and the pin.

Channel ADC source

0 Temperature sensor (not recommended)

1 P31

2 P32

3 P33

4 P34

5 P35

6 VBAT1V-pin

7 VCCBAT-pin

How to improve ADC measurement accuracy:
- To ensure consistent value conversion, add a 10 nF capacitor to ground on the ADC pin.
- Perform linearity calibration on the hardware under test as instructed below:
  - Measure the VBAT reference. Connect a stable 3V power supply to VCCBAT and measure the ADC value of channel 7. The recorded value, referred to as Ymax, is the ADC value at the 0.75V point (VBAT/4). It is recommended to sample multiple boards from the same batch for accurate results.
  - Measure the zero point value. Connect channel 1 (P31) to the board’s GND and measure the ADC value of channel 1. The recorded value, referred to as Ymin, is the ADC value at 0V. If you have multiple samples to test, repeat the process above.
  - Actual measurement. Measure the ADC value of channel x, referred to as Ysample. Convert the measurement to a voltage value in millivolts (mV) using the formula below.
    
    V = 750 × (Ysample − Ymin) ÷ (Ymax − Ymin)
- Input the reference value in tkl_adc.c, as shown below.
```
// The macro definition is located within the tkl_adc.c file.
// Replace it with the actual measured values from the hardware.

#define ADC_CALIC_VAL_0V    ( 16 ) //!< ADC measurement value when connected to GND
#define ADC_CALIC_VAL_0_75V ( 179 ) //!< Connect a standard 3V voltage to VCCBAT, and measure the ADC value.
```
Flash

Operation Time taken (ms)

Erase 4 KB 8 ms

Write 4 KB (erased) 35.8 ms

Read 4 KB 6.89 ms
Key control

P32
- 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

P31

Set this pin to high after entering the main function.

SPI	Feature	Pin
SPI0	CS	P07
SPI0	CLK	P04
SPI0	MOSI	P05
SPI0	MISO	P06

I2C	Feature	Pin
I2C0	SCL	P02
I2C0	SDA	P03

Channel	Pin
0	P10
1	P11
2	P12
3	P13
4	P14
5	P15

Channel	ADC source
0	Temperature sensor (not recommended)
1	P31
2	P32
3	P33
4	P34
5	P35
6	VBAT1V-pin
7	VCCBAT-pin

Operation	Time taken (ms)
Erase 4 KB	8 ms
Write 4 KB (erased)	35.8 ms
Read 4 KB	6.89 ms

Software environment

Install Keil and BK3633 flashing environment.

Keil

Download Keil from the Arm Keil website. mdk528a.exe is recommended. During installation, keep all the default settings.
If you are prompted to install a driver, continue with Install.
When opening Keil, if you are prompted to install a software pack, close the window.
After Keil is installed, add the path of the UV4.exe file to the environment variable. For example, TUYAOS_COMPILE_TOOL: C:\Keil_v5\UV4, as shown below.
Install the legacy pack for Arm7, Arm9, and Cortex-R devices.

Flashing tool

You can flash firmware via serial port. Two flashing tool installers are available in .\vendor\bk3633_ble\sdk\BK3633_DesignKit_V06_2411\Tools\.

bk_writer_V2.00_20231218.exe
BKFIL (recommended)

Software development

Flash and RAM footprint

Disable the testing feature.
```
#define TUYA_SDK_TEST 0
```

Disable Tuya logging.

#define ENABLE_LOG 0
#define BOARD_ENABLE_LOG 0

After a full compilation of the whole project, open the .map file. You will get the RAM and flash footprint.

Firmware flashing

Wire connection

Connect the board’s power, ground, and UART0 (TX: P00, RX: P01) using a USB to TTL converter. Connect the RST signal to the chip reset pin. This enables the script or host to control the RST pin automatically.

Firmware description

The build output is located in .\log\output\app. BK3633 firmware consists of three parts: boot + stack + app.

tuyaos_demo_ble_peripheral_merge_crc.bin = boot + stack + app, the production firmware, supporting UART-based flashing.
tuyaos_demo_ble_peripheral_oad.bin = app, the OTA update firmware, supporting UART-based flashing.
tuyaos_demo_ble_peripheral_stack_oad.bin = stack + app, supporting UART-based flashing. Unless you need to upgrade the stack, this file is generally unnecessary.

Flashing method 1: Chip vendor’s tool

Flash firmware using BKFIL

1: Select the binary file to flash. The selection will be synchronized to the Main screen.
2: Erase All. If needed, check this option to erase the entire flash memory. If you update the code, there is no need to check it.
3: Select Port. Choose the target port and set the baud rate to either 1M or 2M.
4: Select Bin file You can also select the binary file on this screen.
5: Actions. Download the code, erase the flash (erasing the code section only), and read the flash as needed.

Flashing method 2: Tuya flashing tool

Tuya’s chip flashing host software supports the BK3633 platform.

Platform features

Startup time

Use a logic analyzer to measure the signal time difference between the VCC pin and the startup time detection pin.
Detection pins: peripheral → startup time detection pin
Startup time: From power-on to the execution of the main function, it takes about 500 milliseconds.

Flash partition

The BK3633 SiP flash supports either 512 KB or 1 MB. Define the flash specification for your chip by adding a macro in app_config.h, as shown below.

// app_config.h
#define BOARD_CHIP_TYPE 0  //!< 512KB Flash
#define BOARD_CHIP_TYPE 1  //!< 1MB Flash

// Flash
//<0=> 512K flash
//<1=> 1M flash
#ifndef BOARD_CHIP_TYPE
#define BOARD_CHIP_TYPE                         ( 0 )
#endif

512 KB flash partition

1 MB flash partition

Adjust flash partitions

In the original project, you can modify the macros in board.h to adjust the default flash partitions. The following examples provide several possible changes, using 512 KB as a reference.

When the application code size exceeds the default 136 KB, you can compress the unused partition.
When the unused partition that stores the business data is not enough, you can compress the application and OTA partitions.
The unused partition stores testing data by default, which can be allocated to your needs.
In principle, modifying the size of other partitions is not necessary or recommended.

After adjusting the flash partitions, update the parameters in the boot project located at .\vendor\bk3633_ble\sdk\BK3633_DesignKit_V06_2411\SDK\projects\boot. See Adjust boot for details. Copy the generated bk3633_boot.bin and paste it into .\.log\output\boot to replace the existing file.

Start address and size of OTA data

// board.h

#if (BOARD_CHIP_TYPE == 0)
// 512K Flash
#ifndef BOARD_FLASH_TUYA_INFO_START_ADDR
#define BOARD_FLASH_TUYA_INFO_START_ADDR        (0x79000)
#endif

#ifndef BOARD_FLASH_SDK_TEST_START_ADDR
#define BOARD_FLASH_SDK_TEST_START_ADDR         (0x75000)
#endif

#ifndef BOARD_FLASH_OTA_START_ADDR
#define BOARD_FLASH_OTA_START_ADDR              (0x4A000)
#endif

#ifndef BOARD_FLASH_OTA_END_ADDR
#define BOARD_FLASH_OTA_END_ADDR                (0x6C000)
#endif

#ifndef BOARD_FLASH_OTA_SETTING_ADDR
#define BOARD_FLASH_OTA_SETTING_ADDR            (0x7D000)
#endif

#ifndef BOARD_FLASH_OTA_SIZE
#define BOARD_FLASH_OTA_SIZE                    (BOARD_FLASH_OTA_END_ADDR - BOARD_FLASH_OTA_START_ADDR)
#endif

#else
// 1M Flash
#ifndef BOARD_FLASH_TUYA_INFO_START_ADDR
#define BOARD_FLASH_TUYA_INFO_START_ADDR        (0xF9000)
#endif

#ifndef BOARD_FLASH_SDK_TEST_START_ADDR
#define BOARD_FLASH_SDK_TEST_START_ADDR         (0xF5000)
#endif

#ifndef BOARD_FLASH_OTA_START_ADDR
#define BOARD_FLASH_OTA_START_ADDR              (0x75000)
#endif

#ifndef BOARD_FLASH_OTA_END_ADDR
#define BOARD_FLASH_OTA_END_ADDR                (0xC2000)
#endif

#ifndef BOARD_FLASH_OTA_SETTING_ADDR
#define BOARD_FLASH_OTA_SETTING_ADDR            (0xFD000)
#endif

#ifndef BOARD_FLASH_OTA_SIZE
#define BOARD_FLASH_OTA_SIZE                    (BOARD_FLASH_OTA_END_ADDR - BOARD_FLASH_OTA_START_ADDR)
#endif

#endif

Unused partition

// board.h

// Storage address for SDK test data   16K
/**@brief   Define storage SDK test data addr, such as storage bulk data, and product test common data. */
// 512KB Flash
#ifndef BOARD_FLASH_SDK_TEST_START_ADDR
#define BOARD_FLASH_SDK_TEST_START_ADDR         (0x75000)
#endif

// 1MB Flash
#ifndef BOARD_FLASH_SDK_TEST_START_ADDR
#define BOARD_FLASH_SDK_TEST_START_ADDR         (0xF5000)
#endif

Adjust boot

Power consumption

Test method

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 P01 and P00 respectively.
Connect to an ammeter that can provide 3.3V of power, with its positive and negative terminals connected to the +3V pin and the GND pin on the board respectively.
You can measure the power consumption in different modes using power management in the host software.

Power consumption

Measure the average power consumption of typical one-second advertising.
Measure the average power consumption of typical 600-millisecond advertising.
Measure the average power consumption in deep sleep mode. Turn off all peripherals and advertising, maintain RTC and RAM data, and enable GPIO wake-up.

Local clock testing

Choose the 32 kHz clock source for your hardware and specify it in board.h as shown below.

// Select 32K clock, set to 1 to use internal RC32K, and set to 0 to use external 32.768K crystal.
//<0=> external 32.768K crystal
//<1=> internal RC32K
#ifndef BOARD_USED_INTER_RC32K
#define BOARD_USED_INTER_RC32K                  (1)
#endif

The QFN32 supports an external 32 kHz oscillator, while other chip packages rely on the internal RC oscillator. For precise timekeeping, choose a high-precision 16 MHz main oscillator or enable the sub-device to regularly synchronize time with a device such as a Bluetooth gateway.
The QFN48 will soon support an external 32 kHz oscillator on P37.

Hardware testing: A development board from the chip vendor has a 16 MHz crystal oscillator with a frequency tolerance of ±20 ppm and connects to an external 32.768K crystal oscillator. The local clock has a time drift of about two seconds for 24 hours.

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