Under /dev/ there are ttyS0 and ttyS4, but no ttyS2.
UART4 is hardwired to onboard SPI flash chip and so that cannot be used for external UART connection.
That leaves us with UART2.
But in the Mraa demo code, UART2 is not available and only UART4 is available.
Which UART are we suppose to use on RockPi4C running Android 10?
If UART2, how do we go about enabling it?
Thanks.
