+ /* Enable AFIO */
+ stm_rcc.apb2enr |= (1 << STM_RCC_APB2ENR_AFIOEN);
+
+ /* Release PB3, PA15 and PB4 from JTAG use */
+ stm_afio.mapr = (stm_afio.mapr &
+ ~(STM_AFIO_MAPR_SWJ_CFG_MASK << STM_AFIO_MAPR_SWJ_CFG)) |
+ STM_AFIO_MAPR_SWJ_CFG_SW_DP << STM_AFIO_MAPR_SWJ_CFG;