STM32 MCU UART TX current

[KK.4]

I am connecting the STM32L4 MCU UART to silicon labs IC CP2105 (UART to USB converter). The UART to USB bridge is bus powered from the type C connector and the STM32 is separately powered from the battery.

When the CP2105 is in off state ( No USB cable connected),will there be a currently flow from STM32 UART TX pin into the RX pin of CP2105. If so, how to restrict the current consumption when the USB cable is not connected to power CP2105 IC?

[Tesla DeLorean]

Review the datasheet for the CP2105, see if it has any useful features, or if you can identify pins that go low (SUSPEND, CTS, RTS, DTR, etc) when unavailable.

>>..will there be a currently flow from STM32 UART TX pin into the RX pin of CP2105

Perhaps, measure it, I might suspect that the STM32 will parasitically power the CP2105 via this route.