41081 Chapter Notes - Chapter 7: Comparator, Pulse-Width Modulation, Duty Cycle
Chapter 7 – Peripherals
Pulse Width Modulation
• A periodic signal is where the pattern repeats.
• The duty cycle is the percentage of time the signal is high during the period. A signal
with a duty cycle of 50% is called a square wave.
• A pulse width modulator (PWM) is a programmable component that generates
pulses to achieve a specified period and duty cycle.
• A use of a PWM is to control a DC motor. The motor will spin when the input is 1 and
coast when the input is 0. A PWM can be used to achieve the desired spinning
speed.
• O aveage, a PWMs output i tes of eegy, is euivalet to the output’s duty
cycle.
UARTs
• To conserve limited output pins, microcontrollers typically include a hardware device
called a UART that automatically transmits 8 bits of data serially over a single pin.
• UART stands for Universal Asynchronous Receiver/Transmitter
• When dealing with UARTs, receive is written as rx and transmit is written as tx.
• The UART ust e ativated y the uild i RIM“ futio UARTon().
Analog-Digital Conversion
• An analog-to-digital converter (ADC) converts an analog signal to a digital signal,
which a microcontroller program can use.
• An analog signal is a voltage whose value varies continuously over time.
• A digital signal is a series of bits whose binary values represent the voltage level at a
given time.
• A mixed-signal device has a mix of analog and digital inputs and outputs.
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