Bluetooth LE–GR551x

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\GR551x\chip_manual\GR551x_Datasheet_Rev.2.6.pdf.

• Alternatively, check the Goodix website for the latest information.

Development board

• Purchase the development board from the Tuya IoT Development Platform. The part number of the GR5515IENDU_DEMO_NANO development board is 2.03.02.00037.

  Schematic diagram: hardware\GR551x\module_manual\GR5515IENDU-DEMO-NANO_V1.0.0.pdf

  Pin multiplexing: hardware\GR551x\module_manual\GR5515 (Pinmux).xlsx

  

Peripherals

Visit the Goodix website for GR551x chip features and specifications.

• GPIO

  GR5515I and GR5513 have 39 and 22 GPIO pins for multiplexing, respectively, as shown below. For more information, see Pin Mux in hardware\GR551x\chip_manual\GR551x_Datasheet_Rev.2.3.pdf.

  

  The table below shows the mapping between pin numbers and GR551x pin names.

  Pin number	GR551x_pin	Pin number	GR551x_pin	Pin number	GR551x_pin
  TUYA_GPIO_NUM_0	GPIO_0	TUYA_GPIO_NUM_32	AON_GPIO_0	TUYA_GPIO_NUM_40	MSIO_0
  TUYA_GPIO_NUM_1	GPIO_1	TUYA_GPIO_NUM_33	AON_GPIO_1	TUYA_GPIO_NUM_41	MSIO_1
  …	…	…	…	…	…
  TUYA_GPIO_NUM_30	GPIO_30	TUYA_GPIO_NUM_38	AON_GPIO_6	TUYA_GPIO_NUM_43	MSIO_3
  TUYA_GPIO_NUM_31	GPIO_31	TUYA_GPIO_NUM_39	AON_GPIO_7	TUYA_GPIO_NUM_44	MSIO_4

• UART

  GR551x has UART0 and UART1. See the pin multiplexing table for mapping UARTs to GPIOs.

  The default UART definitions for TuyaOS SDK v3.9.0 and later are shown below. Custom pin configurations are supported.

  UART	Feature	Pin	Description
  UART0	TX	GPIO_0	Firmware flashing, authorization, and debugging (APP_UART_ID_0) Flip the second DIP switch to the ON position (towards the main chip).
  UART0	RX	GPIO_1	Flip the first DIP switch to the ON position (towards the main chip).
  UART1	TX	GPIO_7	Log output (APP_UART_ID_1) Flip the fourth DIP switch to the ON position (towards the main chip). You can connect G7 to G10 to use the onboard serial port.
  UART1	RX	GPIO_6	Reserved

  The default UART definitions for TuyaOS SDK v3.8.3 are shown below.

  UART	Feature	Pin	Description
  UART0	TX	GPIO_10	Log output (APP_UART_ID_0)
  UART0	RX	GPIO_11	/
  UART1	TX	GPIO_0	Firmware flashing, authorization, and debugging (APP_UART_ID_1)
  UART1	RX	GPIO_1	/

• SPI

  GR551x has two SPI interfaces (one SPI controller interface with two peripheral chip select pins + one SPI peripheral interface), up to 32 MHz. The SPI controller interface is used by default. You can connect the MISO and MOSI signals together (that is, short the G25 and G16) to perform a loopback test. The default pin definitions:

  SPI	Feature	Pin
  SPIM	CS	GPIO_17 (G17)
  SPIM	CLK	GPIO_24 (G24)
  SPIM	MOSI	GPIO_25 (G25)
  SPIM	MISO	GPIO_16 (G16)

• I2C

  GR551x has two I2C interfaces, supporting 100 kHz, 400 kHz, 1 MHz, and 2 MHz. To display SDK information (TuyaOS demo), the OLED is pre-initialized. I2C0 is used by default.

  I2C	Feature	Pin
  I2C0	SCL	GPIO_30 (G30)
  I2C0	SDA	GPIO_26 (G26)

• PWM

  GR551x supports 6-channel PWM output.

  Channel	GR5515 pin	GR5513 pin	Notes
  0	MSIO_0 (M0)	GPIO_2 (G2)	PWM0_A
  1	MSIO_1 (M1)	GPIO_3 (G3)	PWM0_B
  2	MSIO_2 (M2)	GPIO_4 (G4)	PWM0_C
  3	GPIO_7 (G7)	GPIO_31 (G31)	PWM1_A
  4	GPIO_10 (G10)	GPIO_30 (G30)	PWM1_B
  5	GPIO_11 (G11)	GPIO_26 (G26)	PWM1_C

• ADC

  13-bit ADC, up to 1 Msps, eight channels (five external test channels and three internal signal channels), supporting both single-ended and differential inputs. GR5515 and GR5513 adapt five and two channels of external analog single-ended input, respectively.

  Channel	GR5515 pin	GR5513 pin
  0	MSIO_0 (M0)	MSIO_0 (M0)
  1	MSIO_1 (M1)	MSIO_1 (M1)
  2	MSIO_2 (M2)	None
  3	MSIO_3 (M3)	None
  4	MSIO_4 (M4)	None

• Key control

  AON_GPIO_0 (A0) applies to TuyaOS SDK v3.9.0 and later.

  AON_GPIO_6 (A6) applies to TuyaOS SDK v3.8.3 only.

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

• Startup time detection pin

  GPIO_5 (G5)

  Set this pin to high after entering the main function.

Software environment

Install Keil and GR551x-dependent environment.

Keil

1. Download Keil from the Arm Keil website. mdk528a.exe is recommended. During installation, keep all the default settings.

2. If you are prompted to install a driver, continue with Install.

3. When opening Keil, if you are prompted to install a software pack, close the window.

4. 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.

   

GProgrammer

GProgrammer is a firmware flashing tool that applies to GR551x and GR5526 series. It supports features such as debugging, firmware download, flash read/write, eFuse download, and firmware encryption and signing. In mass production, you can use PLT Lite and GRPLT Lite Config Tool to program and test GR551x and GR5526 series in bulk.

The steps to install GProgrammer are as follows, taking Windows as an example.

1. Visit Goodix website and download GProgrammer (Windows). V1.2.36 or later is recommended.

2. Keep all the default settings and complete the installation.

Develop software

Select chip type

GR551x series offers various packaging types to support diverse applications. CHIP_TYPE supports GR5515 and GR5513. When you develop with different chip platforms, you need to alter the chip type in custom_config.h accordingly.

// <o> Select chip type
// <0=> GR5515
// <1=> GR5513
#ifndef CHIP_TYPE
#define CHIP_TYPE  0
#endif

Flash and RAM footprint

1. Disable the testing feature.

   #define TUYA_SDK_TEST 0
   

2. Disable Tuya logging.

   #define ENABLE_LOG 0
   #define BOARD_ENABLE_LOG 0
   

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

   

Firmware flashing

Wire connection

GR5515ENDU_DEMO_NANO development board comes with a USB to TTL serial port, which can be used for firmware flashing. Connect the hardware and flip all DIP switches to the ON position (towards the GR551x main controller). During the process, the reset operation is done manually.

Before flashing firmware, you need to unlock the flash. Several reset operations are needed in a complete flashing and authorization process. Therefore, it is recommended to connect the RST signal to the chip reset pin using a USB to TTL adapter. This enables the script or host to control the RST pin automatically.

Firmware description

For more information about the compilation output and firmware flashing guide, see .\hex\material\README.md.

Flashing method 1: GProgrammer

Flashing method 2: Command-line tool

The chip vendor’s flash tool GR551x_flash_tool_v1.2.42.1009.exe supports unlocking the flash.

Open .\hex\material\GR551x_flash_tools and double-click the script program.bat to run. If the board is connected to the RST signal, it will be reset automatically in the following process. Otherwise, a manual reset is required.

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 one second, during which 0.5 seconds are used by the program embedded in the chip to detect the serial connection of GProgrammer.

Flash partition

Adjust flash partitions

In the original project, you can modify the macros to adjust the default flash partitions.

• When the application code size exceeds the default 196 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.

Start address of applications

// custom_config.h

// <o> Code load address
// <i> Default: 0x01002000
#define APP_CODE_LOAD_ADDR      0x0100C000

// <o> Code run address
// <i> Default: 0x01002000
#define APP_CODE_RUN_ADDR       0x0100C000

Start address and size of OTA data

// board.h

#ifndef BOARD_FLASH_OTA_START_ADDR
#define BOARD_FLASH_OTA_START_ADDR    (0x0103D000)
#endif

#ifndef BOARD_FLASH_OTA_END_ADDR
#define BOARD_FLASH_OTA_END_ADDR    (0x0106E000)
#endif

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

Unused partition

// board.h

// Address of SDK test data storage, 16K
/**@brief   Define storage SDK test data addr, such as storage bulk data, and product test common data. */
#ifndef BOARD_FLASH_SDK_TEST_START_ADDR
#define BOARD_FLASH_SDK_TEST_START_ADDR         (0x01077000)
#endif

Power consumption

Test method

1. Remove the power indicator LED or series resistor on the NANO board.

   

2. Flip the DIP switch of the USB to TTL converter chip to the OFF position (towards the jumper cap).

3. 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 GPIO_1 and GPIO_0 respectively.

4. Connect to an ammeter that can provide 3.3V of power, with its positive and negative terminals connected to the 3V3 pin and the GND pin on the board respectively.

5. 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 of typical 200-millisecond advertising.

  

• Measure the average power consumption in typical deep sleep mode, with all peripherals turned off, advertising disabled, AON wake-up enabled, and RAM data retained.

  

Local clock testing

The local clock has a time drift of less than one second after operating for over 50 hours.