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4 years ago.
FRDM-K64F UART and VIN power supply
Hi, i'm developing on a project that uses a lot of UARTs on the board. When i use my PC's USB port to supply the FRDM-K64F all UARTs works fine, but when i try to supply the board using VIN pin (5V) seems that UARTs communications are loopbacked, like that RX and TX pins were shorted.
I tried also to supply the board using USB connector with an external USB charger but it did the same thing.
It works correctly only with PC's USB port connected.