GND1VSEL2/TXD2VSEL1/RXD3VSEL0/RXCB4TSEVENT/BUSY5VSEL3/SYNCREQ6GND7VDD1.8_IN8REG189STBY10TESTEN11VDD_IN12SPISCK13SPISO14SPISI15SPICEB16GND17VSEL4/BFULLB18APOFF19CLK16SEL20REFOUT21DACOUT22GND23VDD_IN24RESETB25SIO_ENBL26XIN27XOUT28