Compatibility between Bluetooth 4.0 BLE and traditional Bluetooth

Bluetooth is divided into three categories: Bluetooth Smart Ready, Bluetooth Smart (Smart is the logo for Bluetooth Low Energy), and Standard Bluetooth. According to the Bluetooth SIG, this is to distinguish compatibility between devices and identify the transmission frequency of each version. Basically, Smart Ready is suitable for any dual-mode Bluetooth 4.0 electronic products, such as Apple iPhone 4S and later products and installed Android 4.3 above the system, and Bluetooth chip support 4.0 mobile phone. Smart is a device that uses a twist button battery and transmits a single advisory, such as a heart rate monitor or pedometer. Smart Ready has the highest compatibility and can communicate with Smart and Standards. Standard Bluetooth does not communicate with Smart.

To sum up:

Smart Ready can connect and communicate with Smart Ready, smart, traditional Bluetooth;

Smart can connect and communicate with Smart and Smart Ready;

Traditional Bluetooth can connect and communicate with traditional Bluetooth and Smart Ready;

Since the current mainstream CC2540 is BLE single-mode chip, it belongs to Smart, so it can only connect and communicate with Smart Ready and Smart, which is incompatible with traditional Bluetooth. Devices that support BR and BLE at the same time become dual-mode devices. At present, Bluetooth chips used in general mobile phones are dual-mode. The Bluetooth hardware of my mobile phone supports BLE, but since the system is Android 4.1, you must brush the phone to version 4.3 or above to connect with CC2540.