An Arduino Core for ARM based BLE boards supported by the NimBLE stack.

If you are interested in assisting the development of this project please submit issues and PR's. Or become a collaborator!

• Fully supports the NimBLE-Arduino library on Arm based BLE devices (only Nordic mcu's for now)
• No softdevice, NimBLE provides a complete BLE stack.
• Contains a subset of the EEPROM library to support basic config storage in flash.
• Supports printf and Serial.printf
• Uses/includes FreeRTOS.
• Designed to maximize battery life using tickless idle. This allows the MCU to sleep any time delay is called.
• Custom configuration of FreeRTOS and NimBLE compile options supported by providing a build_opt.h file in your sketch.

I wanted to have a consistent BLE API on all of the devices I work with. NimBLE is the best choice for this as it is the most feature complete and fully open source library available for Arduino.

This Arduino Core does not contain any BLE functionality. It has been designed to support using the NimBLE-Arduino library for BLE operation. Note: Only the release version 1.4.0 and above of NimBLE-Arduino supports Arm devices.

• Generic nRF52840 MCU
• Nordic nRF52840 DK
• Nordic nRF52840 Dongle
• Adafruit CLUE nRF52840
• Adafruit Circuit Playground Bluefruit
• Adafruit Feather nRF52840 Express
• Adafruit Feather nRF52840 Sense
• Adafruit ItsyBitsy nRF52840 Express
• Ebyte E104-BT5040U
• nice!nano v2
• XIAO nRF52840 Sense

• Generic nRF52833 MCU
• Nordic nRF52833 DK
• BBC micro:bit v2

• Generic nRF52832 MCU
• Nordic nRF52832 DK
• RedBear Blend 2
• RedBear Nano 2
• Bluey
• hackaBLE
• hackaBLE_v2
• Adafruit Feather nRF52832
• Ebyte E104-BT5032A-TB

• Generic nRF52810 MCU

• Generic nRF51 MCU
• BBC micro:bit
• Calliope mini
• Bluz DK
• Nordic Semiconductor nRF51822 Development Kit
• Nordic Semiconductor NRF51 Smart Beacon Kit
• Nordic Semiconductor NRF51 Dongle
• OSHChip
• RedBearLab BLE Nano
• RedBearLab nRF51822
• Waveshare BLE400
• ng-beacon
• TinyBLE
• Sino:bit

1. Install PlatformIO
2. Create PlatformIO project and configure a platform option in platformio.ini file:

[env]
platform = https://github.com/h2zero/platform-n-able.git@^1.0.0
framework = arduino
lib_deps = h2zero/NimBLE-Arduino@^1.4.0
board = ...
...

1. Download and install the Arduino IDE (At least v1.6.12)
2. Start the Arduino IDE
3. Go into Preferences
4. Add https://h2zero.github.io/n-able-Arduino/package_n-able_boards_index.json as an "Additional Board Manager URL"
5. Open the Boards Manager from the Tools -> Board menu and install "Arm BLE Boards"
6. Select your board from the Tools -> Board menu

1. Follow steps from Board Manager section above
2. cd <SKETCHBOOK>, where <SKETCHBOOK> is your Arduino Sketch folder:

• OS X: ~/Documents/Arduino
• Linux: ~/Arduino
• Windows: ~/Documents/Arduino

3. Create a folder named hardware, if it does not exist, and change directories to it
4. Clone this repo: git clone https://github.com/h2zero/n-able-Arduino.git
5. Restart the Arduino IDE

1. Arduino Library manager: Go to sketch -> Include Library -> Manage Libraries, search for NimBLE and install version 1.4.0 or greater.
2. Add #include "NimBLEDevice.h" at the beginning of your sketch.

1. Select your board from the Tools -> Board menu
2. Select any options you want
3. Select a programmer (J-Link, ST-Link V2, CMSIS-DAP, Black Magic Probe, adafruit-nrfutil or nrfutil) from the Tools -> "Programmer: " menu
4. Connect your programmer to the device and click Upload

1. Make sure you have Segger J-Link installed on your system.
2. (For Windows) add the JLink.exe path to your environment variables.
3. Select J-Link as the firmware uploader in the tools menu.

1. Install adafruit-nrfutil if not already installed pip install adafruit-nrfutil
2. Select adafruit-nrfutil as the firmware uploader in the tools menu.

Boards with an Adafruit UF2 bootloader, such as the nice!nano v2, can be programmed as follows:

1. In the Arduino IDE, select Sketch -> Export Compiled Binary. UF2 export requires Python 3 to be available on the system path.
2. Double-press the board's reset button (or briefly connect RST to GND twice) to enter the UF2 bootloader and wait for the bootloader drive to mount.
3. Copy the exported .uf2 file to the mounted bootloader drive.

1. Install nrfutil if not already installed pip install nrfutil
2. Select nrfutil as the firmware uploader in the tools menu.

You can change the configuration for many settings by creating a build_opt.h file in your sketch folder. In here you can set compile time definitions for settings that will be included directly on the command line. For example: '-DCONFIG_MAIN_TASK_STACK_SIZE=512' This will set the main task stack size to 512 words (2048 bytes).

• CONFIG_MAIN_TASK_STACK_SIZE - sets the size in 32bit words of the main loop task.
• CONFIG_RTOS_TICK_RATE_HZ - set the tick rate for FreeRTOS (default 1024).
• CONFIG_RTOS_MAX_PRIORITIES - set the maximum priority level for FreeRTOS tasks.
• CONFIG_RTOS_MIN_TASK_STACK_SIZE - set the minimum task stack size.
• CONFIG_RTOS_TIMER_QUEUE_LENGTH - set the queue size for the FreeRTOS timers.
• CONFIG_RTOS_TIMER_STACK_DEPTH - set the timer task stack size in 32bit words.
• CONFIG_RTOS_THREAD_LOCAL_STORAGE_POINTERS - set the number of thread local storage pointers for FreeRTOS tasks (default 1, used for printf buffer management).
• CONFIG_WDT_TIMEOUT_SECONDS - set the number of seconds before the watchdog times out (0 = disable watchdog, default = 0).
• CONFIG_PRINTF_BUFFER_SIZE - set the size of the buffer used for printf and Serial.printf (default 128 bytes, set to 1 for no buffer).
• CONFIG_PRINTF_BUFFER_INDEX - set the FreeRTOS storage pointer index used for managing the printf buffer (default 0).
• USB_CDC_DEFAULT_SERIAL - For devices with USB CDC support, this enables the USB CDC serial by default, set to 0 to disable (default 1), Serial will be redirected to the UART if this is disabled.
• Nimble configuration options can also be included, the list of those can be found here
• Other compiler options or definitions for other libraries can also be specified.

There are a few useful functions available to help with your project.

• uint32_t RTOS.getMainTaskHwm(); - Returns the high water mark of the Main task stack in 32bit words.
• uint32_t RTOS.getIsrStackHwm(); - Returns the high water mark of the ISR stack in 32bit words.
• uint32_t RTOS.getIdleTaskHwm(); - Returns the high water mark of the Idle task stack in 32bit words.
• uint32_t RTOS.getTimerTaskHwm() - Returns the high water mark of the Timer task stack in 32bit words.
• uint32_t RTOS.getBleHostTaskHwm(); - Returns the high water mark of the NimBLE Host task stack in 32bit words.
• uint32_t RTOS.getBleLLTaskHwm() - Returns the high water mark of the NimBLE Link Layer task stack in 32bit words.
• uint32_t RTOS.getFreeHeap(); - Returns the currently free heap size in bytes.

• uint32_t getResetReason(); - Returns the reset reason for the last boot.
• void systemPowerOff(); - Shuts down the MCU.
• void systemRestart(); - Reboot.
• For USB supported boards, additional USB functions beyond CDC are available by including the TinyUSB library (built in) by adding the following to your sketch:

#include "Adafruit_TinyUSB.h"

There are currently three bootloader options available for use with this core, the Adafruit BLE bootloader, the Adafruit serial bootloader, or no bootloader.

On boards that come with Adafruit bootloaders it will be the default option and will work out of the box.

Other boards can optionally use the Adafruit bootloader by selecting it from the tools menu and clicking Burn Bootloader (requires a compatible SWD programmer such as the Segger J-Link). This will install the Adafruit bootloader on the device, which will allow you to upload firmware over USB using the adafruit-nrfutil uploader option. If you do not want to use the Adafruit bootloader you can select "No Bootloader" from the tools menu and click Burn Bootloader to erase any existing bootloader on the device.

• The last four pages of flash, before the bootloader (if applicable) are reserved for user storage and bond information storage (2 pages each).
• Careful attention should be paid to selecting the correct bootloader (tools->Bootloader Type) for your build (if applicable) to ensure the correct linkage.

This core is based on Arduino-nRF5 by Sandeep Mistry, which is based on the Arduino SAMD Core. With some code from Adafruit_nRF52_Arduino

The following libraries are used:

• FreeRTOS as operating system
• nrfx for peripherals driver
• TinyUSB as usb stack