• Attention! GPIO's are 3.3V

    Assigned to Pin Nr. Pin Nr. Assigned to
    3,3V 1 2 5V
    I2C3_SDA_M0 3 4 5V
    I2C3_SCL_M0 5 6 GND
    CPU_REFCLK_OUT 7 8 UART2_TX_M0_DEBUG
    GND 9 10 UART2_RX_M0_DEBUG
    SPI1_MOSI_M1 11 12 UART0_TX
    SPI1_MISO_M1 13 14 UART0_RX
    SPI1_CLK_M1 15 16 GND
    SPI1_CS0_M1 17 18 SPDIF_OUT
    GND 19 20 3,3V

    Source: Page28 https://wiki.pine64.org/images/3/31/Quartz64_model-A_schematic_v1.0_20201215.pdf