Raytac Corporation, A Bluetooth Module Maker based on Nordic nRF51 & nRF52 Solution, (Nordic nRF52840 & nRF52832 & nRF51822 & nRF52810), Bluetooth Specification Version: BT5 & BT4.2 & BT4.1 & BT4.0
Nordic nRF52810 UART service (NUS) Solution (Raytac Module: MDBT42Q-192K)
Nordic released nRF52810 aimed to provide a low entry barrier for developers to explore Bluetooth Low Energy implements.To improve the effective cost, nRF52810 has provided a limited RAM (24K) and Flash Memory (192K) specification.
Among the BLE implements, Raytac is aware that the UART service (as known as NUS, Nordic UART service) is the most common and widely applied service which is used to called as SPP in classic Bluetooth.
Nordic UART Service implementation.
The Nordic UART Service is a simple GATT-based service with TX and RX characteristics. Data received from the peer is passed to the application, and the data received from the application of this service is sent to the peer as Handle Value Notifications. The service is used by the application to send and receive ASCII text strings to and from the peer.
The difference between nRF51 and nRF52 solution depends on the MTU demand.
For more detail, readers can refer to previous article