The TC35661-551 offers the ability to implement secure connections based around ECDH (Elliptic Curve Diffie-Hellman) public key cryptography, a technology adopted by the Bluetooth 4.2 standard. This additional security provides a very high degree of protection against ‘passive eavesdropping’ attacks.
Toshiba notes that Bluetooth Classic and BLE are not interoperable, which means different device protocols and profiles are needed to match the communication method of the host application.
Because the TC35661-551 incorporates both the Serial Port Profile (SPP) required for Bluetooth Classic communication and the Generic Attribute Profile (GATT) used for BLE, the IC supports high-speed serial communication (SPP) as well as all kinds of BLE applications. Standard and proprietary BLE profiles can be attached over the UART interface to the embedded GATT layer.
Toshiba’s original dual-mode IC – the TC35661-501– has, the company says, been produced in tens of millions of pieces per month. As well as adding the BLE 4.2 secure connection feature, the TC35661-551 supports larger MTU packet sizes of 160 bytes. This means that it can deliver higher data transfer rates than its predecessor. In addition, extended GATT functionality supports more complex BLE profiles with larger GATT Server database.
The TC35661-551 can work with operating voltages of 1.8V and 3.3V and integrates UART, I ²C and GPIO interfaces. Sleep mode and host wake-up functions extend battery life. Dimensions of the TFBGA64 package are 5 x 5 mm.