5 Microcontroller
A 8051 microcontroller is built into the SoC to execute the Bluetooth protocols. It operates from 16 MHz to higher frequencies where the firmware can dynamically adjust the trade-off between the computing power and the power consumption.
The MCU core contains Bluetooth stack and profiles, which are hard-coded into ROM to minimize power consumption for the firmware execution and to save the external Flash cost. This core is responsible for the following system functions:
- Boot-up
 - On-the-Air Device Firmware Upgrade (OTA DFU)
 - Executing the Bluetooth stack and Bluetooth profiles
 - Sending the packets to DSP core for audio processing
 - Loading audio codec registers with values read the Flash
 - Managing low-power modes
 - Executing UART commands
 - Device programming
 - GPIO button control
 - PWM control
 - LED control
 - Bluetooth role swap for multi-speakers
 - Adjusting the Bluetooth clock
 - External audio codec control/configuration, if needed
 - USB battery charge detection and configuration of the PMU battery charger
 - Configuration of PMU power regulation
 - Changing the audio subsystem clocks On-the-Fly (OTF) for different audio sampling rates
 
