AVR MCU Mega16 timer experiment report

1. Experimental purpose

Through experiments, master the use of timers, especially the use of timer interrupts!

2. Experimental content

    1 Use the timer0 of the Mega16 microcontroller to generate a 1ms interval timer interrupt (it is recommended to use the application builder, which can use both the Normal working mode and the CTC mode). (1) Implement dynamic refresh of the 4-bit digital tube in the timer interrupt. (2) Design a 100mS time flag in the 1ms timer interrupt, query the time flag in the main program, and realize LED flashing.

    2 Reconfigure TImer0 to work in PWM mode, use the buttons to change the PWM duty cycle and adjust the motor speed;

3. Experimental preparation requirements

Carefully read the examples of timed interrupts in the textbook;

4. Experimental steps

    1 Start ICCAVR, create a project file, configure timer0, implement a 10ms timer interrupt, and use Application Builder to generate initialization code. Note: The IO ports used in this experiment must also be initialized, including the IO used by the digital tube driver, buttons, etc.

    2. Implement the timed refresh of the four-digit digital tube in the timed interrupt (Note: use the driver of HC595 from the last lab class), and implement the 100ms time mark (time stamp) in the timed interrupt, query the time stamp in the main program, and realize the flashing of the LED (any LED of PORTC port can be used);

    3 Reconfigure TImer0 to work in PWM mode, set the initial duty cycle to 10%, and then use the button INT1 (SW8 in the schematic diagram, connected to the PD3 pin of the microcontroller) to change the duty cycle. For example, each time the button is pressed, the duty cycle increases by 10%.

Note: The pins used in the experiment are: PD4, PD5, PD6, PD7, PB0, PB1, PA0, PD3. Please refer to the schematic diagram for the connection of each pin.

Experiment 3: Timer application experiment

Content of report

1. Purpose

   Through experiments, master the use of timers, especially the use of timer interrupts!

2 Experimental content

    1. Use the timer0 of the Mega16 microcontroller to generate a 1ms interval timer interrupt (it is recommended to use the application builder, which can use both the Normal working mode and the CTC mode). (1) Implement dynamic refresh of the 4-digit digital tube in the timer interrupt. (2) Design a 100mS time flag in the 1ms timer interrupt, query the time flag in the main program, and realize LED flashing.

2. Reconfigure TImer0 to work in PWM mode, use the buttons to change the PWM duty cycle and adjust the motor speed;

3 Use the timer0 of the Mega16 microcontroller to generate a timer interrupt with an interval of 1ms (it is recommended to use the application builder, which can use both Normal working mode and CTC mode). Write the working mode used and the values ​​of each timer register.

#include

#include

void port_init(void)

{

PORTA = 0x00;

DDRA = 0x00;

PORTB = 0x00;

DDRB = 0x00;

PORTC = 0x00; //m103 output only

DDRC = 0x00;

PORTD = 0x00;

DDRD = 0x00;

}

//TIMER0 initialize - prescale:8

// WGM: CTC

// desired value: 1000Hz

// actual value: 992.063Hz (-0.8%)

void timer0_init(void)

{

TCCR0 = 0x00; //stop

TCNT0 = 0x83; //set count

OCR0 = 0x7D; //set compare match

TCCR0 = 0x0A; //start timer

}

//call this routine to initialize all peripherals

void init_devices(void)

{

//stop errant interrupts until set up

CLI(); //disable all interrupts

port_init();

timer0_init();

MCUCR = 0x00;

GICR = 0x00;

TIMSK = 0x00; //timer interrupt sources

SEI(); //re-enable interrupts

//all peripherals are now initialized

}

4. Implement dynamic refresh of 4-digit digital tube in timer interrupt. (Only write out the code related to timer interrupt, this part will borrow the driver function of HC595 implemented in the last lab class)

5. Design a 1000mS time flag in the 1ms timer interrupt, query the time flag in the main program, and use the stopwatch function. (Only write the timer interrupt service program and the function code to implement the stopwatch)