ANNA-B402 BLUETOOTH® 5.1 Module (Open CPU) u-blox ANNA-B402 BLUETOOTH® 5.1 Low Energy Module (Open CPU) combines Bluetooth 5.1, an embedded Arm® Cortex®-M4 Microcontroller with FPU and an integrated antenna into a compact 6.5mm x 6.5mm system in package (SiP). The ANNA-B402 Module is based on the Nordic Semiconductor nRF52833 chip. With 512kB flash and 128kB RAM, this device offers the necessary capacity for advanced applications developed with Open CPU architecture and the Nordic SDK. Wired interfaces like UART, USB, SPI, I2C, I2S, and GPIO are available to connect peripheral devices.