/** ****************************************************************************** * @file system_stm32l4xx.c * @author MCD Application Team * @brief CMSIS Cortex-M4 Device Peripheral Access Layer System Source File * * This file provides two functions and one global variable to be called from * user application: * - SystemInit(): This function is called at startup just after reset and * before branch to main program. This call is made inside * the "startup_stm32l4xx.s" file. * * - SystemCoreClock variable: Contains the core clock (HCLK), it can be used * by the user application to setup the SysTick * timer or configure other parameters. * * - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must * be called whenever the core clock is changed * during program execution. * * After each device reset the MSI (4 MHz) is used as system clock source. * Then SystemInit() function is called, in "startup_stm32l4xx.s" file, to * configure the system clock before to branch to main program. * * This file configures the system clock as follows: *============================================================================= *----------------------------------------------------------------------------- * System Clock source | MSI *----------------------------------------------------------------------------- * SYSCLK(Hz) | 4000000 *----------------------------------------------------------------------------- * HCLK(Hz) | 4000000 *----------------------------------------------------------------------------- * AHB Prescaler | 1 *----------------------------------------------------------------------------- * APB1 Prescaler | 1 *----------------------------------------------------------------------------- * APB2 Prescaler | 1 *----------------------------------------------------------------------------- * PLL_M | 1 *----------------------------------------------------------------------------- * PLL_N | 8 *----------------------------------------------------------------------------- * PLL_P | 7 *----------------------------------------------------------------------------- * PLL_Q | 2 *----------------------------------------------------------------------------- * PLL_R | 2 *----------------------------------------------------------------------------- * PLLSAI1_P | NA *----------------------------------------------------------------------------- * PLLSAI1_Q | NA *----------------------------------------------------------------------------- * PLLSAI1_R | NA *----------------------------------------------------------------------------- * PLLSAI2_P | NA *----------------------------------------------------------------------------- * PLLSAI2_Q | NA *----------------------------------------------------------------------------- * PLLSAI2_R | NA *----------------------------------------------------------------------------- * Require 48MHz for USB OTG FS, | Disabled * SDIO and RNG clock | *----------------------------------------------------------------------------- *============================================================================= ****************************************************************************** * @attention * *