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Which timer 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 to generate PWM using timer?
To create the Left-Aligned PWM, a PWM timer counts downward from a specified maxmimum value, called Period (LOAD) value, to zero. When the timer counts to zero, the Period (LOAD) value will be reloaded to the timer and continue to count down..
How PWM timer works?
A PWM timer block diagram. A clock is divided down by a prescaler and applied to a period counter. The duration of the period counter is set with a modulus or period register. The output of the period counter goes to multiple “channels” of pulse width logic.
What is PWM prescaler?
Each of the timers has a prescaler that generates the timer clock by dividing the system clock by a prescale factor such as 1, 8, 64, 256, or 1024. The timers are complicated by several different modes. The main PWM modes are “Fast PWM” and “Phase-correct PWM”, which will be described below.
What is the PWM technique?
Pulse width modulation (PWM) is a modulation technique that generates variable-width pulses to represent the amplitude of an analog input signal. PWM is widely used in ROV applications to control the speed of a DC motor and/or the brightness of a lightbulb.
How does a PWM timer in a microcontroller work?
A PWM timer block diagram A clock is divided down by a prescaler and applied to a period counter. The duration of the period counter is set with a modulus or period register. The output of the period counter goes to multiple “channels” of pulse width logic.
What is the timing resolution of a PWM clock?
I can use a prescaler setting of divide by 8 and a period counter modulus of 60,000 for a PWM period of 20 milliseconds. Now we know the timing resolution for the output pulse. The timing resolution is the period of the 3 MHz clock or 0.333 microseconds.
When does a PWM timer request an interrupt?
PWM timers often have the option of producing an interrupt request when the period counter overflows and when the width logic sees a match (the end of an output pulse). If there are multiple channels, the interrupt service routine would typically read a register in the timer to find out which channel requested the interrupt.
How does a pulse width modulation ( PWM ) work?
Varying speed and direction of a motor’s rotation, as controlled by a PWM signal The period is 20 milliseconds and an active high pulse controls the direction and speed. The motor does not move when the pulse width is 1.5 milliseconds.