Analysis of STM32 Systick timer-EEWORLD

Collect

There is a Systick timer in the ARM Cortex-M3 core, which is a 24-bit countdown timer. When the count reaches 0, it will automatically reload the initial value of the timer from the Load register. As long as the ENABLE in the CTRL register is not cleared to 0, it will never stop. The understanding of the tick timer is mainly divided into the following items:

1. Clock source of tick timer

Looking at the above picture, you may have an illusion that the tick timer is 1/8 of the system clock. In fact, it is not. The clock of the tick timer can be either HCLK/8 or HCLK. This is set through the CTRL register. Knowing this is very important for the clock calculation of the operating system, because the clock time must be calculated accurately.

2. Tick timer register

From here we can see that there are two options for the clock source

3. Tick timer library function

(1) Where are the registers defined? ————In core_cm3.h.

typedef struct {

__IO uint32_t CTRL;

__IO uint32_t LOAD;

__IO uint32_t VAL;

__I uint32_t CALIB;

} SysTick_Type; …

#define SysTick ((SysTick_Type *) SysTick_BASE)

(2) Setting steps

①. Select the clock source

②Set the number of reloads (reload)

③ Enable interrupt

④Start the tick timer

Keywords：STM32 Reference address：Analysis of STM32 Systick timer

Previous article：STM32 uses SysTick for accurate timing
Next article：SysTick timer and delay function

Recommended ReadingLatest update time:2024-11-16 11:27

Solution to the loss of the first character when the STM32 serial port sends characters for the first time

Most of the codes for sending characters on the Internet are as follows: USART_SendData(USART1, (uint8_t)ch); while( USART_GetFlagStatus(USART1, USART_FLAG_TC) != SET); Actually, it makes sense at first glance, but when I read the manual carefully, I found that the TC and TXE flags are set to 1 when reset, so the firs

[Microcontroller]

【STM32】Nested Vectored Interrupt Controller (NVIC)

NVIC, Chinese name Nested Interrupt Vector Controller, is a unique integrated unit inside the Cortex-M3 series controller, which is closely integrated with the CPU, reduces interrupt latency and can handle subsequent interrupts more efficiently. For example, when buying tickets at a train station, the rules and

[Microcontroller]

STM32__main code analysis

The STM32 startup code mainly allocates the stack and sets the vector table, and then jumps to the __main function. The specific code segment to jump to is as follows: view plain copy Reset_Handler PROC EXPORT Reset_Handler IMPORT __main LDR R0, = __mai

[Microcontroller]

Output Compare of stm32 timer

STM32F103VB sends a logic signal to MOC3020 to control the on and off of the BTA16 thyristor. When a zero-crossing signal is detected, the output is 1 after a delay of x milliseconds; the output is turned off after a delay of y milliseconds. This can realize phase-controlled speed regulation of induction motors (low p

[Microcontroller]

In-depth understanding of STM32 memory and bus architecture 1 (based on STM32F411)

This article is reproduced from http://blog.csdn.net/charmingsun/article/details/52258419 Official documentation: STM32F411 Reference ManualSTM32F411 Data SheetCortex™-M4F Programming ManualSTM32 Microcontroller System Memory Boot Mode Application NotesUSART Protocol Used in STM32™ BootloaderARM Cortex™-M

[Microcontroller]

STMicroelectronics is working with AWS and Microsoft to help STM32U5 enable more secure IoT development

STMicroelectronics is strengthening its collaboration with Amazon (AWS) and Microsoft to expand the Internet of Things. On AWS, ST provides a reference that makes it easier and more secure to connect IoT (Internet of Things) devices (STM32U5) to the AWS cloud. At the same time, STMicroelectronics is working with Micro

[Microcontroller]

STM32 small package PD0, PD1 have no external interrupt function

After suffering a loss, I learned my lesson. I got the board back (another night was gone. Where did the engineer's time go? Most of it was wasted like this. I grew up from these failures). When I couldn't adjust it, I looked at the PDF again and found the following: 7.3.2 Use OSC_IN/OSC_OUT pins as GPIO port PD0/PD

[Microcontroller]

stm32 library function learning chapter general timer input capture function

Function: PA8 can drive the LED light to flash with random delay, and connect PA8 to PA7 port with Dupont line. PA7 is the 2nd channel of general timer TIM3. In the TIM3_CH2 trigger interrupt program, the LED light connected to PD2 port is inverted to indicate the interrupt program is running, and the polarity of trigg

[Microcontroller]

stm32 library function learning chapter general timer input capture function

Popular Resources
Popular amplifiers