When routing UART4 using the ECSPI2 pads, register IOMUXC_UART4_RXD_SELECT_INPUT (offset 0x050C) should be changed only when dealing with RX, as its name suggests.
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When routing UART4 using the ECSPI2 pads, register IOMUXC_UART4_RXD_SELECT_INPUT (offset 0x050C) should be changed only when dealing with RX, as its name suggests.