8.Master_I2C_PWM/demo.c

#define F_CPU 16000000UL
#define I2C_FREQ 100000UL
#define I2C_PRESCALER 1
#define I2C_BITRATE ((F_CPU / I2C_FREQ) - 16) / (2 * I2C_PRESCALER)

#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

float pwm_frequency = 1.0;
uint8_t pwm_duty_cycle = 50;

volatile uint8_t pwm_enabled = 0;
volatile uint8_t pwm_changed = 0;

void i2c_init() {
    TWBR = I2C_BITRATE;
}

void i2c_start() {
    TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
    while (!(TWCR & (1 << TWINT)))
        ;
}

void i2c_stop() {
    TWCR = (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
    while (TWCR & (1 << TWSTO))
        ;
}

void i2c_write(uint8_t data) {
    TWDR = data;
    TWCR = (1 << TWINT) | (1 << TWEN);
    while (!(TWCR & (1 << TWINT)))
        ;
}

uint8_t i2c_read_ack() {
    TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA);
    while (!(TWCR & (1 << TWINT)))
        ;
    return TWDR;
}

uint8_t i2c_read_nack() {
    TWCR = (1 << TWINT) | (1 << TWEN);
    while (!(TWCR & (1 << TWINT)))
        ;
    return TWDR;
}

const uint8_t PWM_SLAVE_ADDR = 9;

void pwm_enable() {
    pwm_enabled = 1;
    pwm_changed = 1;
}

void pwm_disable() {
    pwm_enabled = 0;
    pwm_changed = 1;
}

void setPWMFrequency(float frequency) {
    if (frequency < 0 || frequency > 50000.0) {
        return; // Недопустимая частота
    }
    pwm_frequency = frequency;
    pwm_changed = 1;
}

void setPWMDutyCycle(float duty_cycle) {
    if (duty_cycle < 1 || duty_cycle > 100) {
        return; // Недопустимый коэффициент заполнения
    }
    pwm_duty_cycle = duty_cycle;
    pwm_changed = 1;
}

void pwm_check_state() {
    if (pwm_enabled) {
        // Включаем пин ШИМ - реализация зависит от аппаратной платформы
        Serial.print("PWM enabled. Frequency: ");
        Serial.print(pwm_frequency);
        Serial.print(" Hz, duty cycle: ");
        Serial.println(pwm_duty_cycle);
    } else {
        // Выключаем пин ШИМ - реализация зависит от аппаратной платформы
        Serial.println("PWM disabled");
    }
}

void pwm_set_frequency(float frequency) {
    // Устанавливаем частоту ШИМ - реализация зависит от аппаратной платформы
    Serial.print("Setting PWM frequency to: ");
    Serial.println(frequency);
}

void pwm_set_duty_cycle(float duty_cycle) {
    // Устанавливаем коэффициент заполнения ШИМ - реализация зависит от аппаратной платформы
    Serial.print("Setting PWM duty cycle to: ");
    Serial.println(duty_cycle);
}

void enablePWM() {
    pwm_enable();
    // Включаем ШИМ
    sendCommand(0x01, 0.0);
}

void disablePWM() {
    // Выключаем ШИМ
    sendCommand(0x02, 0.0);
    pwm_disable();
}

void increaseFrequency() {
    setPWMFrequency(pwm_frequency * 1.25);
    // Выключаем ШИМ, отправляем команду и включаем обратно
    disablePWM();
    sendCommand(0x03, pwm_frequency);
    enablePWM();
}

void decreaseFrequency() {
    setPWMFrequency(pwm_frequency * 0.8);
    // Выключаем ШИМ, отправляем команду и включаем обратно
    disablePWM();
    sendCommand(0x04, pwm_frequency);
    enablePWM();
}

void increaseDutyCycle() {
    if (pwm_duty_cycle < 100) {
        pwm_duty_cycle+=10;
        setPWMDutyCycle(pwm_duty_cycle);
        // Выключаем ШИМ, отправляем команду и включаем обратно
        disablePWM();
        sendCommand(0x05, pwm_duty_cycle);
        enablePWM();
    } else {
        Serial.println("Maximum duty cycle reached!");
    }
}

void decreaseDutyCycle() {

    if (pwm_duty_cycle > 1) {
        pwm_duty_cycle-=10;
        setPWMDutyCycle(pwm_duty_cycle);
        // Выключаем ШИМ, отправляем команду и включаем обратно
        disablePWM();
        sendCommand(0x06, pwm_duty_cycle);
        enablePWM();
    } else {
        Serial.println("Minimum duty cycle reached!");
    }
}

void checkButton(uint8_t pin, const char* message, void (*command)()) {
    if (bit_is_clear(PINC, pin)) {
        Serial.println(message);
        delay(200);
        command();
    }

    if (pwm_changed) {
        pwm_changed = 0;
        pwm_check_state();
        if (pwm_enabled) {
            pwm_set_frequency(pwm_frequency);
            pwm_set_duty_cycle(pwm_duty_cycle);
        }
    }
}

void setup() {
    i2c_init();
    DDRC &= ~(1 << PINC0) & ~(1 << PINC1) & ~(1 << PINC2) & ~(1 << PINC3) & ~(1 << PINC4) & ~(1 << PINC5);
    PORTC |= (1 << PINC0) | (1 << PINC1) | (1 << PINC2) | (1 << PINC3) | (1 << PINC4) | (1 << PINC5);
    Serial.begin(9600);
    Serial.println("PWM Controller started!");
    sendCommand(0x01, 0.0);
}

void loop() {
    checkButton(0, "Turn on PWM!", enablePWM);
    checkButton(1, "Turn off PWM!", disablePWM);
    checkButton(2, "Increase frequency by 25%!", increaseFrequency);
    checkButton(3, "Decrease frequency by 20%!", decreaseFrequency);
    checkButton(4, "Increase duty cycle by 10%!", increaseDutyCycle);
    checkButton(5, "Decrease duty cycle by 10%!", decreaseDutyCycle);
}


void sendCommand(uint8_t cmd, float value) {
    uint16_t cmd_value;

    switch (cmd) {
        case 0x01:
        case 0x02:
            sendCommandOneByte(cmd);
            break;

        case 0x03:
        case 0x04:
            sendCommandThreeBytes(cmd, value);
            break;

        case 0x05:
        case 0x06:
            sendCommandTwoBytes(cmd, value);
            break;

        default:
            Serial.println("Unknown command");
            break;
    }
}

void sendCommandOneByte(uint8_t cmd) {
    i2c_start();
    i2c_write(PWM_SLAVE_ADDR << 1);
    i2c_write(cmd);
    i2c_stop();

    Serial.print("Sent command: 0x");
    Serial.println(cmd, HEX);
}

void sendCommandTwoBytes(uint8_t cmd, float value) {
    uint16_t cmd_value = round(value);

    i2c_start();
    i2c_write(PWM_SLAVE_ADDR << 1);
    i2c_write(cmd);
    i2c_write(cmd_value & 0xFF);
    i2c_stop();

    Serial.print("Sent command: 0x");
    Serial.print(cmd, HEX);
    Serial.print(", value: ");
    Serial.print(value);
    Serial.print(", cmd value: ");
    Serial.print(cmd_value);
    Serial.print(", data bytes: 0x");
    Serial.println(cmd_value & 0xFF, HEX);
}

void sendCommandThreeBytes(uint8_t cmd, float value) {
    uint16_t cmd_value = round(value * 16); // приводим к 12 бит и 4 бита дробной части
    uint8_t data_bytes[2] = {(cmd_value >> 8) & 0xFF, cmd_value & 0xFF};

    i2c_start();
    i2c_write(PWM_SLAVE_ADDR << 1);
    i2c_write(cmd);
    i2c_write(data_bytes[0]);
    i2c_write(data_bytes[1]);
    i2c_stop();

    Serial.print("Sent command: 0x");
    Serial.print(cmd, HEX);
    Serial.print(", value: ");
    Serial.print(value);
    Serial.print(", cmd value: ");
    Serial.print(cmd_value);
    Serial.print(", data bytes: 0x");
    Serial.print(data_bytes[0], HEX);
    Serial.print(" ");
    Serial.println(data_bytes[1], HEX);
}