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