Adding Project 1 rotary encoder implementations

.gitignore

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+**/.pio/
+**/.vscode/
+.DS_Store
+Thumbs.db

Project_1_Rotary_Encoder/Part_1_Polling/include/digital_in.h

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+#ifndef DIGITAL_IN_H
+#define DIGITAL_IN_H
+
+#include <stdint.h>
+
+class Digital_in
+{
+public:
+    Digital_in(int pin);
+
+    void init();
+
+    bool is_hi();
+    bool is_lo();
+
+private:
+    uint8_t pinMask;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_1_Polling/include/digital_out.h

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+#ifndef DIGITAL_OUT_H
+#define DIGITAL_OUT_H
+
+#include <stdint.h>
+
+class Digital_out
+{
+public:
+    Digital_out(int pin);
+
+    void init();
+    void set_hi();
+    void set_lo();
+    void toggle();
+
+private:
+    uint8_t pinMask;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_1_Polling/include/encoder.h

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+#ifndef ENCODER_H
+#define ENCODER_H
+
+#include <digital_in.h>
+#include <digital_out.h>
+
+class Encoder
+{
+public:
+    Encoder(int c1Pin, int c2Pin, int ledPin);
+
+    void init();
+    void update();
+    int position();
+
+private:
+    Digital_in c1;
+    Digital_in c2;
+    Digital_out led;
+
+    bool previousC1;
+    int count;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_1_Polling/platformio.ini

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+[env:nanoatmega328new]
+platform = atmelavr
+board = nanoatmega328new
+framework = arduino

Project_1_Rotary_Encoder/Part_1_Polling/src/digital_in.cpp

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+#include <digital_in.h>
+#include <avr/io.h>
+
+Digital_in::Digital_in(int pin)
+{
+    pinMask = static_cast<uint8_t>(1U << pin);
+}
+
+void Digital_in::init()
+{
+    // Configure pin as input
+    DDRB &= static_cast<uint8_t>(~pinMask);
+
+    // Enable internal pull-up resistor
+    PORTB |= pinMask;
+}
+
+bool Digital_in::is_hi()
+{
+    return (PINB & pinMask) != 0;
+}
+
+bool Digital_in::is_lo()
+{
+    return (PINB & pinMask) == 0;
+}

Project_1_Rotary_Encoder/Part_1_Polling/src/digital_out.cpp

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+#include <digital_out.h>
+#include <avr/io.h>
+
+Digital_out::Digital_out(int pin)
+{
+    pinMask = static_cast<uint8_t>(1U << pin);
+}
+
+void Digital_out::init()
+{
+    DDRB |= pinMask;
+}
+
+void Digital_out::set_hi()
+{
+    PORTB |= pinMask;
+}
+
+void Digital_out::set_lo()
+{
+    PORTB &= static_cast<uint8_t>(~pinMask);
+}
+
+void Digital_out::toggle()
+{
+    PORTB ^= pinMask;
+}

Project_1_Rotary_Encoder/Part_1_Polling/src/encoder.cpp

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+#include <encoder.h>
+
+Encoder::Encoder(int c1Pin, int c2Pin, int ledPin)
+    : c1(c1Pin), c2(c2Pin), led(ledPin),
+      previousC1(false), count(0)
+{
+}
+
+void Encoder::init()
+{
+    c1.init();
+    c2.init();
+    led.init();
+
+    led.set_lo();
+
+    previousC1 = c1.is_hi();
+    count = 0;
+}
+
+void Encoder::update()
+{
+    led.set_lo();
+
+    bool currentC1 = c1.is_hi();
+
+    if (currentC1 != previousC1)
+    {
+        bool currentC2 = c2.is_hi();
+
+        if (currentC1 == currentC2)
+        {
+            count++;
+        }
+        else
+        {
+            count--;
+        }
+
+        previousC1 = currentC1;
+        led.set_hi();
+    }
+}
+
+int Encoder::position()
+{
+    return count;
+}

Project_1_Rotary_Encoder/Part_1_Polling/src/main.cpp

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+#include <encoder.h>
+
+int main()
+{
+    Encoder encoder(0, 1, 5);
+
+    encoder.init();
+
+    while (1)
+    {
+        encoder.update();
+    }
+
+    return 0;
+}

Project_1_Rotary_Encoder/Part_2_UART/include/digital_in.h

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+#ifndef DIGITAL_IN_H
+#define DIGITAL_IN_H
+
+#include <stdint.h>
+
+class Digital_in
+{
+public:
+    Digital_in(int pin);
+
+    void init();
+
+    bool is_hi();
+    bool is_lo();
+
+private:
+    uint8_t pinMask;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_2_UART/include/digital_out.h

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+#ifndef DIGITAL_OUT_H
+#define DIGITAL_OUT_H
+
+#include <stdint.h>
+
+class Digital_out
+{
+public:
+    Digital_out(int pin);
+
+    void init();
+    void set_hi();
+    void set_lo();
+    void toggle();
+
+private:
+    uint8_t pinMask;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_2_UART/include/encoder.h

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+#ifndef ENCODER_H
+#define ENCODER_H
+
+#include <digital_in.h>
+#include <digital_out.h>
+
+class Encoder
+{
+public:
+    Encoder(int c1Pin, int c2Pin, int ledPin);
+
+    void init();
+    void update();
+    int position();
+
+private:
+    Digital_in c1;
+    Digital_in c2;
+    Digital_out led;
+
+    bool previousC1;
+    int count;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_2_UART/platformio.ini

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+[env:nanoatmega328new]
+platform = atmelavr
+board = nanoatmega328new
+framework = arduino
+monitor_speed = 9600

Project_1_Rotary_Encoder/Part_2_UART/src/digital_in.cpp

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+#include <digital_in.h>
+#include <avr/io.h>
+
+Digital_in::Digital_in(int pin)
+{
+    pinMask = static_cast<uint8_t>(1U << pin);
+}
+
+void Digital_in::init()
+{
+    // Configure pin as input
+    DDRB &= static_cast<uint8_t>(~pinMask);
+
+    // Enable internal pull-up resistor
+    PORTB |= pinMask;
+}
+
+bool Digital_in::is_hi()
+{
+    return (PINB & pinMask) != 0;
+}
+
+bool Digital_in::is_lo()
+{
+    return (PINB & pinMask) == 0;
+}

Project_1_Rotary_Encoder/Part_2_UART/src/digital_out.cpp

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+#include <digital_out.h>
+#include <avr/io.h>
+
+Digital_out::Digital_out(int pin)
+{
+    pinMask = static_cast<uint8_t>(1U << pin);
+}
+
+void Digital_out::init()
+{
+    DDRB |= pinMask;
+}
+
+void Digital_out::set_hi()
+{
+    PORTB |= pinMask;
+}
+
+void Digital_out::set_lo()
+{
+    PORTB &= static_cast<uint8_t>(~pinMask);
+}
+
+void Digital_out::toggle()
+{
+    PORTB ^= pinMask;
+}

Project_1_Rotary_Encoder/Part_2_UART/src/encoder.cpp

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+#include <encoder.h>
+
+Encoder::Encoder(int c1Pin, int c2Pin, int ledPin)
+    : c1(c1Pin), c2(c2Pin), led(ledPin),
+      previousC1(false), count(0)
+{
+}
+
+void Encoder::init()
+{
+    c1.init();
+    c2.init();
+    led.init();
+
+    led.set_lo();
+
+    previousC1 = c1.is_hi();
+    count = 0;
+}
+
+void Encoder::update()
+{
+    led.set_lo();
+
+    bool currentC1 = c1.is_hi();
+
+    if (currentC1 != previousC1)
+    {
+        bool currentC2 = c2.is_hi();
+
+        if (currentC1 == currentC2)
+        {
+            count++;
+        }
+        else
+        {
+            count--;
+        }
+
+        previousC1 = currentC1;
+        led.set_hi();
+    }
+}
+
+int Encoder::position()
+{
+    return count;
+}

Project_1_Rotary_Encoder/Part_2_UART/src/main.cpp

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+#include <Arduino.h>
+#include <encoder.h>
+
+int main()
+{
+    init();
+
+    Encoder encoder(0, 1, 5);
+
+    encoder.init();
+
+    Serial.begin(9600);
+
+    while (1)
+    {
+        encoder.update();
+
+        Serial.println(encoder.position());
+    }
+
+    return 0;
+}

Project_1_Rotary_Encoder/Part_3_Interrupt/include/digital_in.h

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+#ifndef DIGITAL_IN_H
+#define DIGITAL_IN_H
+
+#include <stdint.h>
+
+class Digital_in
+{
+public:
+    Digital_in(int pin);
+
+    void init();
+
+    bool is_hi();
+    bool is_lo();
+
+private:
+    uint8_t pinMask;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_3_Interrupt/include/digital_out.h

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+#ifndef DIGITAL_OUT_H
+#define DIGITAL_OUT_H
+
+#include <stdint.h>
+
+class Digital_out
+{
+public:
+    Digital_out(int pin);
+
+    void init();
+    void set_hi();
+    void set_lo();
+    void toggle();
+
+private:
+    uint8_t pinMask;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_3_Interrupt/include/encoder.h

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+#ifndef ENCODER_H
+#define ENCODER_H
+
+#include <digital_in.h>
+#include <digital_out.h>
+
+class Encoder
+{
+public:
+    Encoder(int c1Pin, int c2Pin, int ledPin);
+
+    void init();
+    void update();
+    int position();
+
+private:
+    Digital_in c1;
+    Digital_in c2;
+    Digital_out led;
+
+    bool previousC1;
+    volatile int count;
+};
+
+#endif

Project_1_Rotary_Encoder/Part_3_Interrupt/platformio.ini

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+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[env:nanoatmega328new]
+platform = atmelavr
+board = nanoatmega328new
+framework = arduino
+monitor_speed = 9600

Project_1_Rotary_Encoder/Part_3_Interrupt/src/digital_in.cpp

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+#include <digital_in.h>
+#include <avr/io.h>
+
+Digital_in::Digital_in(int pin)
+{
+    pinMask = static_cast<uint8_t>(1U << pin);
+}
+
+void Digital_in::init()
+{
+    // Configure pin as input
+    DDRB &= static_cast<uint8_t>(~pinMask);
+
+    // Enable internal pull-up resistor
+    PORTB |= pinMask;
+}
+
+bool Digital_in::is_hi()
+{
+    return (PINB & pinMask) != 0;
+}
+
+bool Digital_in::is_lo()
+{
+    return (PINB & pinMask) == 0;
+}

Project_1_Rotary_Encoder/Part_3_Interrupt/src/digital_out.cpp

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+#include <digital_out.h>
+#include <avr/io.h>
+
+Digital_out::Digital_out(int pin)
+{
+    pinMask = static_cast<uint8_t>(1U << pin);
+}
+
+void Digital_out::init()
+{
+    DDRB |= pinMask;
+}
+
+void Digital_out::set_hi()
+{
+    PORTB |= pinMask;
+}
+
+void Digital_out::set_lo()
+{
+    PORTB &= static_cast<uint8_t>(~pinMask);
+}
+
+void Digital_out::toggle()
+{
+    PORTB ^= pinMask;
+}

Project_1_Rotary_Encoder/Part_3_Interrupt/src/encoder.cpp

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+#include <encoder.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+static Encoder* activeEncoder = nullptr;
+
+ISR(PCINT0_vect)
+{
+    if (activeEncoder != nullptr)
+    {
+        activeEncoder->update();
+    }
+}
+
+Encoder::Encoder(int c1Pin, int c2Pin, int ledPin)
+    : c1(c1Pin), c2(c2Pin), led(ledPin),
+      previousC1(false), count(0)
+{
+}
+
+void Encoder::init()
+{
+    c1.init();
+    c2.init();
+    led.init();
+
+    led.set_lo();
+
+    previousC1 = c1.is_hi();
+    count = 0;
+
+    activeEncoder = this;
+
+    // Enable pin-change interrupts for PORTB
+    PCICR |= (1 << PCIE0);
+
+    // Enable interrupt specifically for PB0 / D8 / C1
+    PCMSK0 |= (1 << PCINT0);
+
+    // Clear any pending PORTB pin-change interrupt
+    PCIFR |= (1 << PCIF0);
+
+    // Enable global interrupts
+    sei();
+}
+
+void Encoder::update()
+{
+    led.set_lo();
+
+    bool currentC1 = c1.is_hi();
+
+    if (currentC1 != previousC1)
+    {
+        bool currentC2 = c2.is_hi();
+
+        if (currentC1 == currentC2)
+        {
+            count++;
+        }
+        else
+        {
+            count--;
+        }
+
+        previousC1 = currentC1;
+
+        led.set_hi();
+    }
+}
+
+int Encoder::position()
+{
+    uint8_t oldSREG = SREG;
+
+    cli();
+    int currentCount = count;
+    SREG = oldSREG;
+
+    return currentCount;
+}

Project_1_Rotary_Encoder/Part_3_Interrupt/src/main.cpp

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+#include <Arduino.h>
+#include <encoder.h>
+
+int main()
+{
+    init();
+
+    Encoder encoder(0, 1, 5);
+
+    encoder.init();
+
+    Serial.begin(9600);
+
+    while (1)
+    {
+        Serial.println(encoder.position());
+    }
+
+    return 0;
+}

README.md

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+# Embedded System Projects
+
+## Project 1 - Rotary Encoder Driver
+
+This repository contains the three implementations developed for Project 1 in T-738-EMBE.
+
+### Part 1 - Polling
+Basic polling-based rotary encoder driver.
+
+### Part 2 - UART
+Polling-based encoder driver with continuous Serial output at 9600 baud.
+
+### Part 3 - Interrupt
+Interrupt-based encoder driver using a pin-change interrupt on C1.