CMSIS Cortex-M0+ Device Peripheral Access Layer System Source File. More...

#include "stm32u0xx.h"

Macros
#define	VECT_TAB_OFFSET 0x0U

#define	ENABLE_DBG_SWEN

Functions
void	SystemInit (void)
	Setup the microcontroller system.

void	SystemCoreClockUpdate (void)
	Update SystemCoreClock variable according to Clock Register Values.

Variables
uint32_t	SystemCoreClock = 4000000U

const uint8_t	AHBPrescTable [16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9}

const uint8_t	APBPrescTable [8] = {0, 0, 0, 0, 1, 2, 3, 4}

const uint32_t	MSIRangeTable [12]

Detailed Description

CMSIS Cortex-M0+ Device Peripheral Access Layer System Source File.

Author: MCD Application Team

Attention

This software is licensed under terms that can be found in the LICENSE file in the root directory of this software component. If no LICENSE file comes with this software, it is provided AS-IS.

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_stm32u0xx.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_stm32u0xx.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

APB Prescaler | 1

HSI Division factor | 1

PLL_M | 1

PLL_N | 8

PLL_P | 7

PLL_Q | 2

PLL_R | 2

Require 48MHz for RNG | Disabled

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Macros

Functions

Variables