system_stm32f4xx.c File Reference

Detailed Description

CMSIS Cortex-M4 Device Peripheral Access Layer System Source File.

Author

MCD Application Team

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_stm32f4xx.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.

Attention

© Copyright (c) 2017 STMicroelectronics. All rights reserved.

This software component is licensed by ST under BSD 3-Clause license, the "License"; You may not use this file except in compliance with the License. You may obtain a copy of the License at: opensource.org/licenses/BSD-3-Clause

Definition in file system_stm32f4xx.c.

Functions
static void	SystemInit_ExtMemCtl (void)
	Setup the external memory controller. Called in startup_stm32f4xx.s before jump to main. This function configures the external memories (SRAM/SDRAM) This SRAM/SDRAM will be used as program data memory (including heap and stack).
void	SystemInit (void)
	Setup the microcontroller system Initialize the FPU setting, vector table location and External memory configuration.
void	SystemCoreClockUpdate (void)
	Update SystemCoreClock variable according to Clock Register Values. The SystemCoreClock variable contains the core clock (HCLK), it can be used by the user application to setup the SysTick timer or configure other parameters.

Variables
uint32_t	SystemCoreClock = 16000000
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}

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