mirror of
https://codeberg.org/eel4746_piano/avr_piano.git
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94 lines
1.5 KiB
C
94 lines
1.5 KiB
C
/*
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* EEL4746C - AVR Piano - Speaker Section
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* speaker is connected to PD2 and ground, PD3-7
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* the LCD Arduino UNO is connected to TX/RX (PD0/1)
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*/
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#include <avr/io.h>
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#include <avr/interrupt.h>
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#define T1_PRESCALAR 8
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#define FREQ(f) (16e6 / f / T1_PRESCALAR / 2)
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#define P_RX 0
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#define P_TX 1
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#define P_SPKR 2
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unsigned short freqs[] = {
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FREQ(100),
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FREQ(200),
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FREQ(250),
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FREQ(300),
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FREQ(350),
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FREQ(400),
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FREQ(500),
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FREQ(600),
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FREQ(700),
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FREQ(750),
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FREQ(1000),
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FREQ(1250),
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FREQ(1500),
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FREQ(1750),
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FREQ(2000),
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FREQ(3000),
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FREQ(4000),
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FREQ(5000),
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FREQ(6000),
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FREQ(7000),
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FREQ(8000),
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};
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unsigned char note = 8;
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unsigned char buttonpressed = 1;
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int
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main(void)
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{
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// Data Direction for Buttons, UART, Speaker
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DDRB = 0x00;
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DDRC = 0x00;
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DDRD = (1 << P_TX) | (1 << P_SPKR);
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// Enabling Pin Change Interrupt for All Buttons
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PCMSK0 = 0xFF;
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PCMSK1 = 0xFF;
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PCMSK2 = ~(1 | (1 << 1) | (1 << 2));
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PCICR = (1 << PCIE0) | (1 << PCIE1) | (1 << PCIE2);
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TCCR1A = 0x00; // use timer1 CTC mode
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TCCR1B = 1 << WGM12; // already prescaled by 8 in table
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sei();
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// Sends Square wave to the Speaker When a Button is Pressed
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for (unsigned char n = 0;; n = (n + 1) % 2) {
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if (!buttonpressed && n == 0) continue;
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// Prepare Timer/Counter
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TCNT1 = 1;
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OCR1A = freqs[note];
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TCCR1B |= 1 << CS11;
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while ((TIFR1 & (1 << OCF1A)) == 0); // Monitor OutPut Compare Flag
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// Toggles port For Speaker
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PORTD ^= 1 << P_SPKR;
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TIFR1 |= 1 << OCF1A;
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TCCR1B &= ~(1 << CS11);
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}
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}
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ISR (PCINT0_vect)
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{
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}
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ISR (PCINT1_vect)
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{
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}
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ISR (PCINT2_vect)
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{
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}
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