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What is input capture Mode?
Input capture is a method of dealing with input signals in an embedded system. Embedded systems using input capture will record a timestamp in memory when an input signal is received. The interrupts can be programmed to occur at the rising or falling edge of the input signal, depending on requirements.
What is input capture pin?
The input capture (IC) event is a hardware event tied to the logical state of one of the input pins on PORTA. We begin by connecting an external TTL level signal to pins PA2, PA1, or PA0 on PORTA. So, for example, if we set pin IC1I in TMSK1 , then the occurrence of an input capture event on pin PA2 will do two things.
What is the purpose of input capture Mode of the timer?
The Input Capture module is used to capture a timer value from one of two selectable time bases on the occurrence of an event on an input pin. The Input Capture features are useful in applications requiring frequency (Time Period) and pulse measurement.
What is timer capture mode?
“Capture” mode saves the current timer value into the CCP registers when a specific event occurs (usually a transition on the CCP pin). “Compare” mode continually compares the value in the CCP register with the timer value, and triggers an interrupt or a transition on the CCP pin when the two values match.
What is PWM capture?
The Capture/Compare/PWM module is a peripheral that allows the user to time and control different events, and to generate Pulse-Width Modulation (PWM) signals. In Capture mode, the peripheral allows the timing of the duration of an event.
What is TCCR1B?
If the time between interrupts is supposed to be equal every time, the CTC bit has to be set (TCCR1B). It is a 16-bit register (see note at the beginning of the register section). ICR1. The Input Capture register can be used to measure the time between pulses on the external ICP pin (Input Capture Pin).
What is general purpose timer?
The General Purpose Timer (GPT) has a 32-bit up-counter. The GPT can also generate an event on the DO_CMPOUTn pins and an interrupt when the timer reaches a programmed value. The GPT has a 12-bit prescaler, which provides a programmable clock frequency derived from multiple clock sources.
What is difference between compare and capture?
Capture mode – retrieves a timer value based on a signal event. Compare mode – constantly monitors a timer counter value and compares it to a value set in the application. Compare mode will trigger an event when the values match.
How does output compare work?
Output compare is the ability to trigger an output based on a timestamp in memory, without interrupting the execution of code by a processor or microcontroller. The corresponding ability to record a timestamp in memory when an input occurs is called input capture.
What is input capture STM32?
As the name implies, Input capture is used to capture the input signal given to the microcontroller and measures its frequency and pulse width. In this tutorial, I will only cover the frequency part and the pulse width will be covered in next one where we will use PWM Input to do that.
Which timer is used in PWM mode?
We will use the simplest timer, TIMER0 for PWM generation. So we have an 8 bit counter counting from 0 to 255 and then resetting to 0 and so on.
How are STM32 timers used in input capture mode?
STM32 Timers In Input Capture Mode In Input capture mode, the Capture/Compare Registers (TIMx_CCRx) are used to latch the value of the counter after a transition detected by the corresponding ICx signal. When a capture occurs, the corresponding CCXIF flag (TIMx_SR register) is set and an interrupt or a DMA request can be sent if they are enabled.
How does input capture work in sleep mode?
In Sleep mode, the Input Capture (ICx) pin can only function as an external interrupt source for wake-up. The Sleep mode is enabled by setting the Input Capture Mode bits (ICM<2:0> = 111). In this mode, if the input capture interrupt is enabled, a rising edge on the capture pin generates capture interrupt.
How does a STM32 capture and compare channel work?
Each Capture/Compare channel is built around a capture/compare register (including a shadow register), an input stage for capture (with a digital filter, multiplexing, and Prescaler) and an output stage (with comparator and output control). The input stage samples the corresponding TIx input to generate a filtered signal TIxF.
How is TIX input used in slave mode?
The input stage samples the corresponding TIx input to generate a filtered signal TIxF. Then, an edge detector with polarity selection generates a signal (TIxFPx) which can be used as trigger input by the slave mode controller or as the capture command.