Protocol over UART for Real-Time Applications

Nowadays, high-speed interfaces are used for data transfer between Internet of Things (IoT) devices or different wearable devices. However, embedded microcontrollers are still equipped with low-speed interfaces as universal asynchronous receiver/transmitter (UART), serial peripheral interface (SPI) or inter-integrated circuit (I2C). These interfaces provide the physical layer for sending or receiving sensor data. The main advantages being the low power associated for driving the interfaces and the low price for having them as integrated peripheral in the microcontroller. Besides being a local communication interface, UART can also be used for inter-device communication (e.g. device status, sending erroneous messages, performing software update). In the previous scenarios, UART data transmission is not safe and can be prone to errors. The paper presents a framing that improves UART communication for real-time embedded devices. Beside the message frame also a message handle service is implemented such that the communication process does not interfere with the device's real-time operation.