[io_mux]
gpio pad f0 f1 f2 f3 f4 notes
0 GPIO0 GPIO0 SPI_CS2 - - CLK_OUT
1 U0TXD U0TXD SPI_CS1 GPIO1 CLK_RTC_BK U0RTS UART TX during flash programming
2 GPIO2 GPIO2 I2SO_WS U1TXD - U0TXD UART TX during flash programming
3 U0RXD U0RXD I2SO_DATA GPIO3 CLK_XTAL_BK U0CTS UART Rx during flash programming
4 GPIO4 GPIO4 CLK_XTAL - - -
5 GPIO5 GPIO5 CLK_RTC - - -
6 SDIO_CLK SD_CLK SPI_CLK - GPIO6 U1CTS Connect to SD_CLK (Series R: 200Ω)
7 SDIO_DATA_0 SD_DATA0 SPI_MISO - GPIO7 U1TXD Connect to SD_D0 (Series R: 200Ω)
8 SDIO_DATA_1 SD_DATA1 SPI_MOSI - GPIO8 U1RXD Connect to SD_D1 (Series R: 200Ω)
9 SDIO_DATA_2 SD_DATA2 SPIHD - GPIO9 HSPIHD Connect to SD_D2 (Series R: 20Ω)
10 SDIO_DATA_3 SD_DATA3 SPIWP - GPIO10 HSPIWP Connect to SD_D3 (Series R: 200Ω)
11 SDIO_CMD SD_CMD SPI_CS0 - GPIO11 U1RTS Connect to SD_CMD (Series R: 200Ω)
12 MTDI MTDI I2SI_DATA HSPI_MISO GPIO12 U0DTR
13 MTCK MTCK I2SI_BCK HSPI_MOSI GPIO13 U0CTS
14 MTMS MTMS I2SI_WS HSPI_CLK GPIO14 U0DSR
15 MTDO MTDO I2SO_BCK HSPI_CS GPIO15 U0RTS
16 XPD_DCDC GPIO16 - - - - Deep-sleep wakeup (need to be connected to EXT_RSTB)