你去看一下RM手册中的IOMUX Controller (IOMUXC)部分,弄清楚寄存器的定义。
附上部分说明:
• SW_MUX_CTL: Selects the primary or alternate function of a pin, and enables
loopback mode when applicable.
• SW_SELECT_INPUT: Controls pin input path. This register is only required when
multiple pads drive the same internal port.
• SW_PAD_CTL: Controls pad slew rate, driver strength, pull-up/down resistance, and
so on.