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What is SysTick interrupt?
SysTick is a simple timer that is part of the NVIC controller in the Cortex-M microprocessor. Its intended purpose is to provide a periodic interrupt for an RTOS, but it can be used for other simple timing purposes.
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.
What is tick in microcontroller?
If the microcontroller is a dance floor then the clock ticks are the rhythm that all the peripherals and the processor dance to!
What is the purpose of the NVIC controller?
In short, the role of NVIC is to decode priorities of each interrupt and handle them according to their interrupt number and priority. NVIC helps to prioritize the interrupts and it helps in reducing the interrupt latency.
What happens when the systick interrupt is raised?
The SysTick interrupt is executed (logic high) then the ADC interrupt is tail chained and will run when the SysTick ends. The SysTick interrupt is raised which starts the ADC conversion. The ADC finishes conversion and raises its interrupt before the SysTick interrupt completes so it enters a Pending state.
How does a vectored interrupt controller ( NVIC ) work?
The current state of the program is preserved. The NVIC initiates a call to that vector table, locates the interrupt number that has occurred, picks the address of the service routine from that vector table. After that, the service corresponding to the interrupt is executed.
Can a systick be set to a pending state?
Only interrupts are configurable through the NVIC registers, and SysTick is not an interrupt. NVIC registers have no place for negative IRQ numbers, in bitmasks or elsewhere. SysTick can indeed be set to a pending state, but that’s done through SCB->ICSR, not in NVIC.