I have an implementation using SPI after my first iteration using UART. I've been focusing on how low the voltage can be before it ceases to operate.
UART can successfully transmit down to 1.9V and SPI only 2.45V. The SPI lines seem to cease operating. My MCU can continue to toggle pins, ANT seems dead.
I didn't expect the interface to have different voltage requirements, so if there's some other explanation, I'd appreciate hearing about it.
