n-able Arduino core

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!

Features

• 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.

Why?

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.

BLE

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.

Supported boards

nRF52840

• 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

nRF52833

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

nRF52832

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

nRF51

• 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

Installing

Platformio

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 = ...
...

Arduino Board Manager

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

From git (for core development)

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

Install NimBLE-Arduino

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.

Flashing your device

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

Uploading via Segger J-Link

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.

Uploading via adafruit-nrfutil (for Adafruit bootloader devices only)

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

Uploading via (Nordic) nrfutil (for Nordic bootloader devices only)

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

Configuration (optional)

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).

Configuration option list

• 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_WDT_TIMEOUT_SECONDS - set the number of seconds before the watchdog times out (0 = disable watchdog, default = 0).
• 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.

API

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

RTOS class functions

• 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.

General system functions

• uint32_t getResetReason(); - Returns the reset reason for the last boot.
• void systemPowerOff(); - Shuts down the MCU.
• void systemRestart(); - Reboot.

Bootloader

Currently only some boards have Adafruit bootloaders available which are provided as options. You may choose to use the bootloader or none. The provided Adafruit bootloaders have no softdevice, if you currently are using the softdevice based Adafruit bootloader on your nRF52 board you will need to update it to the one provided by selecting it from the boards menu and clicking Burn Bootloader.

For boards without the Adafruit bootloader option clicking Burn Bootloader will simply erase the flash memory on the device. This is required if you have any bootloader flashed already.

Important notes

• 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.

Credits

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