USART, FreeRTOS and C++ on nRF51

Now that we have set up the programming environment the next thing I personally like to implement on any microcontroller is a simple UART communication. Since it is really simple to do using nRF51 SDK, I thought of explaining how to implement USART and FreeRTOS in C++. Even though C is a very capable language on its own I feel restricted without OOP, I know some people might disagree but personally OOP enables me to structure my code better and is easier to pick it up after couple months of idle time. Nonetheless, this article won’t cover FreeRTOS in details; it is expected from you to know more or less what is an RTOS and what is it capable of. Also I prefer not to use printf/scanf whenever I can in embedded projects due to its large memory footprint. Since we will have the luxury of C++ we will implement a similar “Serial” library to Arduino. Honestly serial library is one of the things people behind Arduino got right.

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Starting with nRF51 BLE and Qt Creator

Recently I came across an interesting little ARM Cortex M0 microcontroller nrf51822, which has an integrated low energy Bluetooth (BLE)  and overall is a very capable to do other tasks besides BLE especially due to its immense FLASH memory  and RAM which is 256kb and 32kb accordingly (varies between models).  Immediately I thought of trying to make a simple smart-watch for various reasons like low energy mode, which I think was 0.1µA in sleep mode.  Only drawback compared to other ARM Cortex series microcontrollers is that it’s not really the fastest in the market, however a new one will be coming soon by first quarter of 2016, which will be more efficient, faster and overall more capable SOC. Luckily for us, their SDKs are pretty much identical, and once you learn and understand how nrf51 series SDK is structured and how to use it then switching to nrf52 shouldn’t be a problem. In any case I bought the development board BLE400 which is pictured above to play around; nonetheless I highly recommend buying the original nrf51-DK board just to support Nordic for developing an awesome micro.

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