What is minimum voltage for MKL27Z64VLH4 (or similar M0+) to work as USB device? Is it possible to use it as 1.8V like on attached picture?
If I understood right, during working as crystalless USB device, internal precise 48 MHz clock can be used also as source for master (or for other peripherals) clock.
I found FlexIO AN for UART, I2C, SPI, PWM. Is there any FlexIO SWD (master) open source example?