8.Master_I2C_PWM/main.c

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

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;

bool pwm_enabled = true;
float pwm_frequency = 1000.0;
float pwm_duty_cycle = 0.5;


void pwm_enable() {
    pwm_enabled = true;
    pwm_check_state();
}

void pwm_disable() {
    pwm_enabled = false;
    pwm_check_state();
}

void setPWMFrequency(float frequency) {
    pwm_frequency = frequency;
    if (pwm_enabled) {
        pwm_set_frequency(pwm_frequency);
    }
}

void setPWMDutyCycle(float duty_cycle) {
    pwm_duty_cycle = duty_cycle;
    if (pwm_enabled) {
        pwm_set_duty_cycle(pwm_duty_cycle);
    }
}


void pwm_check_state() {
    if (pwm_enabled) {
        pwm_set_frequency(pwm_frequency);
        pwm_set_duty_cycle(pwm_duty_cycle);
        Serial.print("PWM enabled. Frequency: ");
        Serial.print(pwm_frequency);
        Serial.print(" Hz, duty cycle: ");
        Serial.println(pwm_duty_cycle);
    } else {
        pwm_set_duty_cycle(0.0);
        Serial.println("PWM disabled");
    }
}

void pwm_set_frequency(float frequency) {
    // TODO: Implement PWM frequency setting logic
    Serial.print("Setting PWM frequency to: ");
    Serial.println(frequency);
}

void pwm_set_duty_cycle(float duty_cycle) {
    // TODO: Implement PWM duty cycle setting logic
    Serial.print("Setting PWM duty cycle to: ");
    Serial.println(duty_cycle);
}


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

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

void increaseFrequency() {
    setPWMFrequency(pwm_frequency * 1.25);
    sendCommand(0x03, pwm_frequency);
}

void decreaseFrequency() {
    setPWMFrequency(pwm_frequency * 0.8);
    sendCommand(0x04, pwm_frequency);
}


void increaseDutyCycle() {
    if (pwm_duty_cycle < 0.9) {
        setPWMDutyCycle(pwm_duty_cycle + 0.1);
        sendCommand(0x05, pwm_duty_cycle);
    } else {
        Serial.println("Maximum duty cycle reached!");
    }
}

void decreaseDutyCycle() {
    if (pwm_duty_cycle > 0.1) {
        setPWMDutyCycle(pwm_duty_cycle - 0.1);
        sendCommand(0x06, pwm_duty_cycle);
    } 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(1000);
        command();
    }
}

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 = ((uint16_t)cmd << 8) | (uint16_t)(value * 16);
//   uint8_t upper_byte = cmd_value >> 8;
//   uint8_t lower_byte = cmd_value & 0xFF;

//   i2c_start();
//   i2c_write(PWM_SLAVE_ADDR << 1);
//   i2c_write(cmd);
//   i2c_write(upper_byte);
//   i2c_write(lower_byte);
//   i2c_stop();

//   Serial.print("Sent command: 0x");
//   Serial.print(cmd, HEX);
//   Serial.print(", value: ");
//   Serial.print(cmd_value / 16);
//   Serial.print(", cmd value: ");
//   Serial.print(cmd_value);
//   Serial.print(", data bytes: 0x");
//   Serial.print(upper_byte, HEX);
//   Serial.print(" ");
//   Serial.println(lower_byte, HEX);
// }

void sendCommand(uint8_t cmd, float value) {
    uint16_t cmd_value = (uint16_t)(value * 16);

    uint8_t upper_byte = cmd_value >> 8;
    uint8_t lower_byte = cmd_value & 0xFF;

    i2c_start();
    i2c_write(PWM_SLAVE_ADDR << 1);
    i2c_write(cmd);
    i2c_write(upper_byte);
    i2c_write(lower_byte);
    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(upper_byte, HEX);
    Serial.print(" ");
    Serial.println(lower_byte, HEX);
}