ST STM32F2 User Manual

Overview of HAL drivers
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2.12.2 HAL initialization
2.12.2.1 HAL global initialization
In addition to the peripheral initialization and de-initialization functions, a set of APIs are
provided to initialize the HAL core implemented in file stm32f2xx_hal.c.
HAL_Init(): this function must be called at application startup to
initialize data/instruction cache and pre-fetch queue
set SysTick timer to generate an interrupt each 1ms (based on HSI clock) with
the lowest priority
call HAL_MspInit() user callback function to perform system level initializations
(Clock, GPIOs, DMA, interrupts). HAL_MspInit() is defined as “weak” empty
function in the HAL drivers.
HAL_DeInit()
resets all peripherals
calls function HAL_MspDeInit() which a is user callback function to do system
level De-Initalizations.
HAL_GetTick(): this function gets current SysTick counter value (incremented in
SysTick interrupt) used by peripherals drivers to handle timeouts.
HAL_Delay(). this function implements a delay (expressed in milliseconds) using the
SysTick timer.
Care must be taken when using HAL_Delay() since this function provides an accurate
delay (expressed in milliseconds) based on a variable incremented in SysTick ISR.
This means that if HAL_Delay() is called from a peripheral ISR, then the SysTick
interrupt must have highest priority (numerically lower) than the peripheral interrupt,
otherwise the caller ISR will be blocked.
2.12.2.2 System clock initialization
The clock configuration is done at the beginning of the user code. However the user can
change the configuration of the clock in his own code. Please find below the typical Clock
configuration sequence:
static void SystemClock_Config(void)
{
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_OscInitTypeDef RCC_OscInitStruct;
/* Enable HSE Oscillator and activate PLL with HSE as source */
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON; RCC_OscInitStruct.PLL.PLLState =
RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 25; RCC_OscInitStruct.PLL.PLLN = 240;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = 5;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
/* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks
dividers */
RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK |
RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_3); }

ST STM32F2 Specifications

General

Brand	ST
Model	STM32F2
Category	Microcontrollers
Language	English