Optimized the calibration mechanism in the SDK. For ICs with large frequency offsets, calibration will be performed with higher frequency.

Fixed a bug that could cause errors during ADC multi-channel sampling, and enhanced stability of the ADC driver.

Fixed a bug for the PMU calibration strategy.

Optimized the restriction on stack usage in the NVDS module.

Optimized advertising APIs.

Optimized high/low temperature strategy.

Supported GCC Hardware Floating Point Unit.

Added an AON WDT API to read the reset flag.

Fixed a bug for APP UART asynchronous data APIs.

Optimized the logic to calculate the quantity of handles in Bluetooth LE Protocol Stack.

Optimized the business logic to start advertising.

Optimized Bluetooth LE functionalities and fixed several issues: Changed the Bluetooth LE event handling method from using callback functions to message event distribution; fixed the memory leak and timing configuration issues in the 2.4G proprietary protocol module, as well as a configuration error in the single carrier wave register.

Optimized peripheral driver functionalities and fixed issues for modules such as I2C, BOD, RTC, Timer, SPI, and ADC.

Changed the usage of peripheral drivers, including optimizing peripheral transfer APIs and related parameters, simplifying the usage of peripheral APIs, as well as specifically optimizing the driver architecture and API calling method for the DMA module.

Removed peripheral driver functionalities, including signal amount APIs, app_aes, app_hmac, app_systick, app_rtos_cfg, and Flash suspend/resume APIs.

Removed HAL drivers and FreeRTOS driver.

Removed some example projects and fixed several issues: Removed example projects such as ble_basic_example, ble_app_hrs_gh3011, and ble_app_wechat; fixed issues in example projects such as ble_app_hids_keyboard and ble_app_wss.

Applied the same firmware upgrade solution to all Bluetooth LE SoCs; added the app_bootloader example project to replace the functionality of example projects such as ble_dfu_boot, ble_dfu_fast, and second_boot.

Added the ble_app_multi_slave example project, which demonstrates Bluetooth LE multi-slave and multi-connection functionalities.

In the direct_test_mode example project, supported setting the TX power for single carrier wave tests, and added the functionalities of starting and stopping advertising.

Supported Fault Trace functionality in GCC.

Upgraded the Keil download algorithm.

Adds support for GR5513BENDU

Adds support for broadcasting with a non-resolvable address when privacy mode is enabled

Adds support for ARM CMSIS DSP library files

Adds the app log store module to support log export via Bluetooth LE

In app_i2c module, adds a member variable slave_addr for current slave address recording in the app_i2c_evt_t structure, to facilitate obtaining slave address from the callback functions registered at the application layer

In app_adc module, adds an app_adc_multi_channel_conversion_async API/span>

In app_timer module, limits the maximum app_timer timing duration to 1 hour to eliminate the risk of app_timer overflow

Optimizes parameters for app_pkc_montgomery_inversion_sync and app_pkc_montgomery_inversion_async APIs

Deletes DMA mode for FreeRTOS-related APIs (app_aes_encrypt_sem_sync and app_aes_decrypt_sem_sync) in AES module

Fixes a bug that may cause low-probability of Bluetooth LE disconnection in multi-connection RTOS scenarios when the SoC is in sleep mode

Adds sys_ble_static_addr_policy_reverse interface to support Bluetooth MAC address algorithm policy selection and solve the problem of OTA upgrade failure due to Bluetooth MAC address algorithm policy updates

Updates Flash download algorithm from GR551x_8MB_Flash.FLM to GR5xxx_16MB_Flash.FLM

Adds support for GR5515I0NDA and GR5515IENDU System-on-Chips (SoCs). GR5515I0NDA, which can be configured to GR5515I0ND, supports low-voltage (typical: 1.8 V) external Flash. Developed based on GR5515IGND, GR5515IENDU is a new GR551x model with an embedded Flash of 512 KB

The application layer supports broadcasting of 31 bytes in nondiscoverable or broadcast mode

Adds support for multiple MTU exchanges by default

Optimizes the power consumption of Wait for Interrupt (WFI) during broadcasting in the FreeRTOS

Optimizes RAM space

Adds the RAM RESERVE SECTION region to scatter files, and addsthe RESERVE_RAM_SECTION macro to the SDK to define variables that should not be cleared

Optimizes I2C, QSPI, SPI, and UART drivers, and decouples interrupt operations from DMA operations

Improves the delay_us() API function to avoid system breakdown when the function was called concurrently by multiple tasks

Fixs a bug that could cause unexpectedly high packet error rate at the RX end when the modulation index of the TX signals is small while the frequency offset is large

Fixs a bug that could cause overflow when calculating diff_us of the real-time clock based on BLE timer

Optimizes the overall power consumption of the SoCs

Adds the function of specifying advertising channels

Adds a module which supports storing logs in Flash

Adds an API to parse resolvable private address (RPA)

Optimizes the Fast DFU module to boost upgrade speed and to provide better compatibility

Adds an exflash read API to boost the speed in accessing Flash

Adds an exflash read API to boost the speed in accessing Flash

Optimizes relevant exflash APIs to save the space for storing RAM code

Fixes several problems which used to undermine the stability of the system and Bluetooth Low Energy performance

Updates software contained in the SDK accordingly

Supports GR5513BEND and GR5515I0ND SoCs

Supports the use of RNG2 as a low-power clock

Optimizes the overall power consumption performance of GR551x SoCs

Adds SPI-V2 driver to support 32-bit SPI fast transmission

Adds APIs to operate the eFuse at the user layer

Adds some middlewares in the library to facilitate the user to manage the Bluetooth Low Energy (Bluetooth LE) activities and schedule the business at the application layer

Fixes several issues that affect the stability of the system and Bluetooth LE

Optimizes the throughput in the one-master-multiple-slave scenario

Adds the new feature of minimum 937.5 μs connection interval and the corresponding demo

Supports wide voltage Flash

Updates the tools in SDK

Offers BLE 5.0 full featured API, such as master/slave, scan/broadcast role, 2M/coded PHY

Comprehensive on-chip peripheral drivers (including SPI, I2C, UART, TIMER and others), supporting low power automatic management of peripheral devices

Abundant BLE application and peripheral sample projects, including common BLE profile and service

Sample projects based on FreeRTOS and a variety of practical middleware

Supports Keil/GCC integrated development environment, and provides API manual based on Doxygen

Supports firmware/data encryption and OTA firmware upgrade

Provides GRToolbox (Android), GRUart (Windows), GRSmart (Windows), GProgrammer (Windows)