UART Connection

J4220UX and J4214U

UART:
VEXT – This is the Logic High, VOH voltage. In 3.3V logic, tie it to 3.3V, in 5V logic, tie it to 5V.
5V – This is supply voltage. Do not supply 3.3V here.
GPIO:
GPO1 and GPO2 – Active Low Open Drain. Must provide at pullup resistor. Maximum continuous load current 35mA.
GPI1 and GPI2 – High Impedance input.