K1 Pro GPIO 扩展接口
K1 Pro预留了一个40Pin的GPIO扩展接口，采用2.54双列直插的座子，方便爱好者们可以根据自 己的需求连接外设，扩展不同的功能。我们的系统会将这些IO默认设置为一些特定功能，但是用户可以通过软件的重新配置使这些通用的IO具备一些特殊的功能，因为这些IO都是多功能复用的引脚。
1.多功能引脚定义列表
所有的GPIO都可以设置成通用的输入或者输出，也能通过内核配置成更多功能。下面的表格给我们展示了各个GPIO的扩展功能。
| Pin Number | Pin Definition |
|---|---|
| 1 | 3.3V |
| 2 | 5.0V |
| 3 | PWM2_CH1_M2/I2C6_SDA_M2/UART4_RX_M0/SAI4_SDO_M3/ETH1_RXD0_M0/ GPIO2_D1_d |
| 4 | 5.0V |
| 5 | PWM2_CH0_M2/I2C6_SCL_M2/UART4_TX_M0/SAI4_SDI_M3/ETH1_TXCTL_M0/GPIO2_D0_d |
| 6 | GND |
| 7 | CAN0_TX_M2/I2C4_SCL_M1/UART6_TX_M0/SPI3_MOSI_M2/FLEXBUS0_D13_M1/PDM1_SDI3_M1/SAI4_SCLK_M0/GPIO4_A4_d |
| 8 | PWM2_CH2_M2/I3C1_SCL_M0/UART6_TX_M1/SAI4_MCLK_M3/ETH1_RXD1_M/CAM_CLK0_OUT_M1/GPIO2_D2_d |
| 9 | GND |
| 10 | PWM2_CH3_M2/I3C1_SDA_M0/UART6_RX_M1/ETH1_RXCTL_M0/GPIO2_D3_d |
| 11 | CAN0_RX_M2/I2C4_SDA_M1/UART6_RX_M0/SPI3_MISO_M2/FLEXBUS0_D14_M1/PDM1_CLK0_M1/SAI4_LRCK_M0/GPIO4_A6_ |
| 12 | PWM2_CH4_M2/I2C9_SDA_M2/UART6_RTSN_M1/ETH1_MDC_M0/ISP_PRELIGHT_TRIG_M0/GPIO2_D4_d |
| 13 | PWM2_CH6_M0/SPI3_CLK_M2/SAI4_SDI_M0/SAI1_SDO0_M0/GPIO4_A7_d |
| 14 | GND |
| 15 | UART2_RTSN_M1/UART6_RTSN_M0/UART5_TX_M1/SPI4_CLK_M2/FLEXBUS1_D13_M1/PDM1_CLK1_M1/SAI1_SDI3_M0/SAI1_SDO1_M0/GPIO4_B0_d |
| 16 | PWM2_CH5_M2/I2C9_SCL_M2/UART6_CTSN_M1/ETH1_MDIO_M0/ISP_FLASH_TRIGOUT_M0/GPIO2_D5_d |
| 17 | 3.3V |
| 18 | PWM2_CH6_M2/I3C1_SDA_PU_M0/UART9_RTSN_M0/SPDIF_RX0_M2/SAI3_MCLK_M2/ETH0_MCLK_M1/ETH_CLK1_25M_OUT_M0/CAM_CLK1_OUT_M1/GPIO2_D6_d |
| 19 | I2C7_SDA_M1/SPI3_MOSI_M0/UART3_RX_M0/SAI3_LRCK_M2/ETH0_MDC_M1/ETH1_PPSTRIG_M0/VI_CIF_VSYNC/GPIO3_A1_d |
| 20 | GND |
| 21 | MIPI_TE_M1/CAN1_TX_M3/SPI3_MISO_M0/UART3_CTSN_M0/SPDIF_RX1_M1/SAI3_SDO_M2/ETH0_RXCTL_M1/ETH1_PPSCLK_M0/VI_CIF_CLKO/GPIO3_A2_d |
| 22 | PWM1_CH0_M3/SPI2_CLK_M2/UART1_CTSN_M2/FLEXBUS0_CSN_M0/FLEXBUS1_D11/DSMC_RDYN/SAI4_SDI_M1/ETH_CLK0_25M_OUT_M0/VO_EBC_SDSHR/VO_LCDC_D23/GPIO3_A4_d |
| 23 | I2C7_SCL_M1/SPI3_CLK_M0/UART3_TX_M0/SAI3_SCLK_M2/ETH0_MDIO_M1/VI_CIF_HREF/GPIO3_A0_d |
| 24 | CAN1_RX_M3/SPI3_CSN0_M0/UART3_RTSN_M0/SPDIF_TX1_M1/SAI3_SDI_M2/ETH0_RXD1_M1/ETH1_PTP_REFCLK_M0/VI_CIF_CLKI/GPIO3_A3_d |
| 25 | GND |
| 26 | PWM0_CH0_M3/SPI2_MOSI_M2/UART10_RX_M0/FLEXBUS0_D8/DSMC_CSN1/SAI4_MCLK_M1/ETH0_MCLK_M0/VO_EBC_SDCE3/VO_LCDC_D19/GPIO3_B0_d |
| 27 | I2C7_SDA_M2/UART3_RX_M1/FLEXBUS0_CSN_M1/FLEXBUS1_D13_M0/FLEXBUS0_D14_M0/DSMC_INT2/SAI4_SDO_M1/CAM_CLK2_OUT_M0/SPDIF_TX0_M1/VO_POST_EMPTY/GPIO4_A1_d |
| 28 | MIPI_TE_M2/I2C7_SCL_M2/SPI1_CSN1_M2/UART3_TX_M1/FLEXBUS1_CSN_M3/FLEXBUS1_D14_M0/FLEXBUS0_D13_M0/DSMC_INT0/SAI4_LRCK_M1/CAM_CLK1_OUT_M0/SPDIF_RX0_M1/GPIO4_A0_d |
| 29 | MIPI_TE_M0/SPI4_MISO_M2/FLEXBUS1_D15_M1/PDM1_SDI1_M1/SAI1_SDI1_M0/SAI1_SDO3_M0/GPIO4_B2_d |
| 30 | GND |
| 31 | CAN1_RX_M2/I2C3_SDA_M0/UART2_RX_M1/FLEXBUS0_CSN_M4/SPDIF_RX0_M0/GPIO4_B4_d |
| 32 | PWM2_CH2_M3/SPI1_MISO_M2/UART8_RX_M0/FLEXBUS1_D6/DSMC_DATA4/SAI1_SDO0_M1/VO_EBC_SDDO6/VO_LCDC_D6/GPIO3_C5_d |
| 33 | CAN1_TX_M2/PCIE0_CLKREQN_M2/I2C3_SCL_M0/UART2_TX_M1/FLEXBUS0_D15_M1/SPDIF_TX0_M0/GPIO4_B5_d |
| 34 | GND |
| 35 | CAN0_TX_M3/I2C5_SCL_M3/SPI2_CSN0_M2/UART11_TX_M0/FLEXBUS1_D7/DSMC_DATA5/SAI1_SDO1_M1/VO_EBC_SDDO7/VO_LCDC_D7/GPIO3_C4_d |
| 36 | SPI1_MOSI_M2/UART8_TX_M0/FLEXBUS1_D5/DSMC_DATA3/SAI1_LRCK_M1/VO_EBC_SDDO5/VO_LCDC_D5/GPIO3_C6_d |
| 37 | PWM2_CH2_M3/SPI1_MISO_M2/UART8_RX_M0/FLEXBUS1_D6/DSMC_DATA4/SAI1_SDO0_M1/VO_EBC_SDDO6/VO_LCDC_D6/GPIO3_C5_d |
| 38 | PWM2_CH3_M3/SPI1_CSN0_M2/UART8_CTSN_M0/FLEXBUS1_D3/DSMC_DATA1/SAI1_MCLK_M1/VO_EBC_SDDO3/VO_LCDC_D3/GPIO3_D0_d |
| 39 | GND |
| 40 | PWM2_CH3_M1/CAN1_RX_M1/SPI4_CLK_M0/I2C6_SDA_M3/VP2_SYNC_OUT/SAI4_SCLK_M2/GPIO4_C7_d |
备注：
电压
板子上所有的3.3V，5V和地都是不能配置的，剩下的所有引脚都是3.3V的，也就是说GPIO的输入和输出都是3.3V的，当然这些引脚从芯片端并不是3.3V，而是通过电平转换将所有的IO都转换成3.3V。
输入输出
GPIO的高电平设置为3.3V,低电平是0V。