What is SysTick_Handler?
What is SysTick_Handler?
It is a blinky that tests the system clock speeds. It takes a number of system clock ticks to be used as the period and initialises the system tick timer and its interrupt and leaves it running. Your code must implement a service routine called SysTick_Handler() which is called every time the systick event fires.
What is the SysTick?
The System Tick Time (SysTick) generates interrupt requests on a regular basis. For applications that do not require an OS, the SysTick can be used for time keeping, time measurement, or as an interrupt source for tasks that need to be executed regularly.
What is PendSV?
PendSV (Pendable SerVice) is an interrupt request is used by the OS to force a context switch if no other interrupt is active. SVCall (SuperVisor Call) is triggered by the SVC instruction and is used by the FreeRTOS to start the scheduler.
How do I turn off SysTick timer?
How do I disable the SysTick interrupt or timer? There are two bits within the SysTick Control and Status Register (SYST_CSR) that control the SysTick timer. To disable the SysTick interrupt, clear the TICKINT bit (bit 1). To disable the SysTick counter, clear the ENABLE bit (bit 0).
Are interrupts synchronous?
An interrupt is usually defined as an event that alters the sequence of instructions executed by a processor. Synchronous interrupts are produced by the CPU control unit while executing instructions and are called synchronous because the control unit issues them only after terminating the execution of an instruction.
What is reload value?
The RELOAD value is calculated according to its use. For example, to generate a multi-shot timer with a period of N processor clock cycles, use a RELOAD value of N-1. If the SysTick interrupt is required every 100 clock pulses, set RELOAD to 99.
What’s new in stm32f4xx?
Look for all functions in library or API documentation for STM32F4xx libraries provided from me. From this moment, there is new delay system. First system used Systick timer to make an interrupts every 1us. This allows us great accuracy in microseconds but not so nice for processor and interrupts.
What is the use of systick timer for interrupts?
First system used Systick timer to make an interrupts every 1us. This allows us great accuracy in microseconds but not so nice for processor and interrupts. Also, Systick can be used for RTOS and then it become incompatible for my delay. For that purpose, lib has been changes. now you have 2 options for delay:
What is the maximum speed of stm32f429?
Libraries where you might (not needed to) have problems if you are using ARM-GCC (Coocox, etc) compiler and variable-based delay for microseconds: There might be also somewhere.. STM32F429 can go up to 180MHz.
