Timer-Counter 0 in AVR Microcontrollers

Timer/Counter 0 is one of the timers integrated into the ATmega328 microcontroller. It is an 8-bit timer used to generate precise time delays, measure time intervals, and produce PWM (Pulse Width Modulation) signals. This timer can be configured in different modes, including normal, CTC (Clear Timer on Compare Match), and PWM (Pulse Width Modulation) modes. It is commonly used for generating time delays, controlling motors, and generating specific frequencies in embedded systems.

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🔗 Resources

Here you'll find a collection of useful links and videos related to the topic of AVR microcontrollers.

TIMER0 Overview
├── Documentation
│   ├─ [TIMER0 Modes]
│   │   ├─ Registers — TCCR0A, TCCR0B (WGM bits)
│   │   ├─ Modes — Normal, CTC, Fast PWM, Phase Correct PWM
│   │   └─ Examples — Mode switching and timing behavior
│   │
│   ├─ [TIMER0 Prescaler]
│   │   ├─ Register — TCCR0B (CS02:0)
│   │   ├─ Prescaler — Clock division and timer speed
│   │   └─ Effects — Impact on overflow and resolution
│   │
│   ├─ [TIMER0 Interrupts]
│   │   ├─ Registers — TIMSK0, TIFR0
│   │   ├─ Sources — Overflow, Compare Match A/B
│   │   └─ Control — Enable, flag clear, and ISR guide
│   │
│   ├─ [TIMER0 Outputs]
│   │   ├─ Registers — TCCR0A (COM bits), OC0A/B
│   │   ├─ Modes — Toggle, Clear, Set (normal/inverting)
│   │   └─ Usage — External output waveforms
│   │
│   ├─ [TIMER0 Other Registers]
│   │   ├─ TCNT0 — Timer/counter value
│   │   ├─ OCR0A — Compare match A value
│   │   └─ OCR0B — Compare match B value
│   │
│   ├─ [TIMER0 Time Calculation]
│   │   ├─ Inputs — TCNT0, OCR0A, prescaler
│   |   └─ Output — Overflow and match intervals
│   │
│   └─ [TIMER0 PWM Calculation]
│       ├─ Modes — Fast PWM, Phase Correct
│       └─ Math — PWM frequency and duty cycle
│
└── Registers
    ├─ [TCCR0A]  — Output Compare behavior & Waveform Generation Mode (Part 1)
    ├─ [TCCR0B]  — Clock Source selection, Prescaler setting & WGM bits (Part 2)
    ├─ [TCNT0]   — Timer/Counter register — Holds current timer count
    ├─ [OCR0A]   — Output Compare Register A — Match value for Channel A
    ├─ [OCR0B]   — Output Compare Register B — Match value for Channel B
    ├─ [TIMSK0]  — Interrupt Mask Register — Enable Timer0 interrupts
    └─ [TIFR0]   — Interrupt Flag Register — Indicates interrupt events

Tip

The resources are detailed in the sections below.
To access any of them, simply click on the corresponding blue link.

• TIMER0 Modes

  This document provides a detailed overview of all waveform generation modes of Timer0, including Normal, CTC, Fast PWM, and Phase Correct PWM, with register configurations and practical examples.

• TIMER0 Prescaler

  This document explains how to configure the clock source and prescaler for Timer0, including detailed descriptions of all clock select bits and their effects on timer resolution and overflow frequency.

• TIMER0 Interrupts

  This file covers all interrupt-related features of Timer0 such as overflow, compare match A/B interrupts, and explains how to enable and clear them properly using TIMSK0 and TIFR0 registers.

• TIMER0 Outputs

  This document explains Compare Output Modes and how they affect the OC0A and OC0B pins in different timer modes, with practical configuration examples for normal, inverting, and non-inverting outputs.

• TIMER0 Other Registers

  This file provides a detailed description of Timer0 data and compare registers: TCNT0, OCR0A, and OCR0B. It explains how each register works, including bit-level information and their roles in compare match operations for Channel A and B.

• TIMER0 Time Calculation

  This document helps calculate the overflow time and compare match intervals in Normal and CTC modes based on prescaler and system clock, with practical examples and formulas.

• TIMER0 PWM Calculation

  This file shows how to calculate the output PWM frequency for Timer0 in both Fast PWM and Phase Correct PWM modes, using OCR0A as TOP and different prescaler settings.

Videos Overview

AVR, Timer and PWM
   ├── [aKaReZa 59 - AVR, Timer, Accurate Time - Mode 1]
   │   ├─ Timer0 — Normal and CTC modes overview.
   │   ├─ Interrupts — Overflow vs Compare Match.
   │   ├─ Precision — Execution time and interval measurement.
   │   └─ Display — 7-segment usage + digit splitting method.
   │
   ├── [aKaReZa 105 - AVR, Timer, PWM - Mode 2]
   │   ├─ PWM Modes — Fast and Phase Correct (TOP variations).
   │   ├─ Comparison — OCR updates and waveform structure.
   │   ├─ Dual Slope — Signal symmetry and advantages.
   │   └─ Dead Time — Use cases in motor and power control.
   │
   └── [aKaReZa 108 - AVR, Servo Motor]
       ├─ Servo PWM — 50Hz signal generation and tuning.
       ├─ Timer1 — Mode 14 (Fast PWM) and Mode 10 (Phase Correct).
       └─ Precision — Angle control and signal comparisons.

aKaReZa 59 – AVR, Timer, Accurate Time, Mode 1 Learn about Timer-Counter 0 in AVR microcontrollers, Normal and CTC modes, Overflow and Compare Match interrupts, precise timing, function execution time calculation, and 7-segment display integration.
aKaReZa 105 – AVR, Timer, PWM - Mode 2 A deep dive into PWM modes in AVR microcontrollers, covering Fast and Phase Correct PWM, dual slope advantages, Dead Time, and real-world applications in motors, converters, and LED drivers. Ideal for mastering PWM in practical engineering contexts.
aKaReZa 108 – AVR, Servo Motor Learn how to control a servo motor using AVR timers by generating precise 50Hz PWM signals. This video covers Timer0 basics, advanced Timer1 modes (Mode 14 and Mode 10), and high-precision angle control—perfect for mastering servo control in embedded systems.

• AVR Microntroller

  This repository contains comprehensive resources for AVR microcontrollers, including hardware schematics, software libraries, and educational projects.

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Note

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