The XE1431 is a Bluetooth System-on-Chip based on the Semtech Bluetooth Sequencer, which includes a fully programmable 8-bit application microcontroller, a high speed UART, SPI interface, RC oscillator, power management unit, and an on-chip voice CODEC. The purpose of the XE1431 is to offer a very high level of integration requiring a minimum of external components to build complete voice and data applications while maintaining design flexibility.