My customer used TM4C1232 UART for communication, when they do the hardware signal test, sometimes it will cause the P16(U0RX), P17(U4RX) broken. When test these two pins resistor according GND, it decrease to 200~600 Ω. Normally these two pin should in tri-state when power off and the resistor is infinite.
This also cause the RX signal voltage level decrease to 1.96v.
And customer want to know M4 GPIO physical model, which help them to analysis why will happen this condition? Do someone have this ?