111 lines
1.8 KiB
C
111 lines
1.8 KiB
C
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#include <avr/io.h>
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#include <util/delay.h>
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#include <avr/interrupt.h>
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#include <stdio.h>
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void togglePin(uint8_t port, uint8_t pin);
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void initCtcTimer0(void);
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void initOverflowTimer0(void);
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void initOverflowTimer1(void);
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void initUart(unsigned int baud);
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void uart_sendByte(uint8_t byte);
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int uart_printf(char var, FILE *stream);
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static FILE stream = FDEV_SETUP_STREAM(uart_printf, NULL, _FDEV_SETUP_WRITE);
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uint8_t sec = 0;
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int main()
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{
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stdout = &stream;
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/* Make PB1 & PB2 an output pin */
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DDRB |= (1 << DDB1);
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DDRB |= (1 << DDB2);
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/* With this frequency, it is 38,4k baud */
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initUart(12);
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while (1) {
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_delay_ms(1000);
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printf("Seconds passed: %u\n\r", sec++);
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}
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return 0;
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}
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void initCtcTimer0(void)
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{
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/* Initialize counter 0 */
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TCNT0 = 0;
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/* Enable Counter0 Compare Match A Interrupt */
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TIMSK0 |= (1 << OCIE0A);
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/* Select clock. Prescaler of 0*/
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TCCR0B |= (1 << CS00);
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/* Use CTC Mode */
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TCCR0A |= (1 << WGM01);
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/*
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* OCR0A contains TOP value for counter:
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*/
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OCR0A = 200;
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}
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void initOverflowTimer0(void)
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{
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/* Prescaler = 0 */
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TCCR0B |= (1<<CS00);
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/* Enable Timer Overflow Interrupt */
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TIMSK0 |= (1<<TOIE0);
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}
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void initOverflowTimer1(void)
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{
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TCCR1B |= (1<<CS11);
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TIMSK1 |= (1<<TOIE1);
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}
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ISR(TIMER0_COMPA_vect)
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{
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PORTB ^= (1 << PB2);
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}
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void initUart(unsigned int baud)
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{
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/* Set baud rate */
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UBRR1H = (unsigned char)(baud>>8);
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UBRR1L = (unsigned char)baud;
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/* Enable receiver and transmitter */
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UCSR1B = (1<<RXEN1)|(1<<TXEN1);
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/* Set frame format */
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UCSR1C |= (3<<UCSZ10); // 8 data bits
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// UCSR1C &= ~(1<<USBS1); // 1 stop bit
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}
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void uart_sendByte(uint8_t byte)
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{
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/* Wait for empty transmit buffer */
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while (!(UCSR1A & (1<<UDRE1)))
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{
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}
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/* Put data into buffer, sends the data */
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UDR1 = byte;
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}
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int uart_printf(char var, FILE *stream)
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{
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uart_sendByte(var);
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return 0;
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}
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