Support for low power modes
Without sleep mode and wakeup sources, battery powering a Sphere is not really feasible.
Modern microcontrollers support several low power modes, wakeup sources and peripherals that can receive data while the core is sleeping / in low power mode. For example: periodically receiving data thru UART from an external sensor; slow-speed ADC sampling directly to memory with DMA; Periodic wake-up by RTC to read an I2C / SPI connected sensor. I assume the Sphere processors are capable of these, but SDK support is missing.
An example scenario would be:
- The application processor would be used for communication, mostly sleeping / off. A real-time core for data acquisition.
- Halting or sending the application processor to sleep, and sending the low power / sleep mode as well.
- The real time processor would be woken up either by RTC, or interrupt from external sources.
- Sending the data if / when Wifi is available. Triggered by user (a button press), or retrying periodically.