Hi, My test board can enter sleep mode OK, but doesn't wake up when PC13 goes high: (never reach __enable_irq())  void Sleep() { __disable_irq(); SysTick->CTRL = 0; // Enable WKUP4 (PC13) PWR->WKUPEPR = PWR_WKUPEPR_WKUPEN4; // Enable WKUP4 PWR->WKU...