Reset and clock control (RCC)
#define: RCC_UART5CLK_SYSCLK ((uint32_t)0x50400000)
#define: RCC_UART5CLK_LSE ((uint32_t)0x50800000)
#define: RCC_UART5CLK_HSI ((uint32_t)0x50C00000)
RCC_USB_Device_clock_source
#define: RCC_USBCLKSource_PLLCLK_1Div5 ((uint8_t)0x00)
#define: RCC_USBCLKSource_PLLCLK_Div1 ((uint8_t)0x01)