Posted on December 15, 2017 at 08:28I'm looking at the STM32F301R8 datasheet (DocID 025146, https://www.st.com/resource/en/datasheet/stm32f301r8.pdf Rev.7)On page 41 it lists PB4/AF6=I2S3ext_SD and PB5/AF6=I2S3_SDOn page 45 it lists PB4/AF6=I2S3_SD ...