kopia lustrzana https://github.com/k3ng/k3ng_cw_keyer
49 wiersze
2.5 KiB
C++
49 wiersze
2.5 KiB
C++
// ---------------------------------------------------------------------------
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// Created by Tim Eckel - teckel@leethost.com
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// Copyright 2013 License: GNU GPL v3 http://www.gnu.org/licenses/gpl-3.0.html
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//
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// See "NewTone.h" for purpose, syntax, version history, links, and more.
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// ---------------------------------------------------------------------------
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#include "NewTone.h"
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unsigned long _nt_time; // Time note should end.
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uint8_t _pinMask = 0; // Pin bitmask.
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volatile uint8_t *_pinOutput; // Output port register
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void NewTone(uint8_t pin, unsigned long frequency, unsigned long length) {
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uint8_t prescaler = _BV(CS10); // Try using prescaler 1 first.
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unsigned long top = F_CPU / frequency / 4 - 1; // Calculate the top.
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if (top > 65535) { // If not in the range for prescaler 1, use prescaler 256 (61 Hz and lower @ 16 MHz).
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prescaler = _BV(CS12); // Set the 256 prescaler bit.
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top = top / 256 - 1; // Calculate the top using prescaler 256.
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}
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if (length > 0) _nt_time = millis() + length; else _nt_time = 0xFFFFFFFF; // Set when the note should end, or play "forever".
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if (_pinMask == 0) {
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_pinMask = digitalPinToBitMask(pin); // Get the port register bitmask for the pin.
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_pinOutput = portOutputRegister(digitalPinToPort(pin)); // Get the output port register for the pin.
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uint8_t *_pinMode = (uint8_t *) portModeRegister(digitalPinToPort(pin)); // Get the port mode register for the pin.
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*_pinMode |= _pinMask; // Set the pin to Output mode.
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}
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ICR1 = top; // Set the top.
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if (TCNT1 > top) TCNT1 = top; // Counter over the top, put within range.
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TCCR1B = _BV(WGM13) | prescaler; // Set PWM, phase and frequency corrected (ICR1) and prescaler.
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TCCR1A = _BV(COM1B0);
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TIMSK1 |= _BV(OCIE1A); // Activate the timer interrupt.
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}
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void noNewTone(uint8_t pin) {
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TIMSK1 &= ~_BV(OCIE1A); // Remove the timer interrupt.
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TCCR1B = _BV(CS11); // Default clock prescaler of 8.
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TCCR1A = _BV(WGM10); // Set to defaults so PWM can work like normal (PWM, phase corrected, 8bit).
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*_pinOutput &= ~_pinMask; // Set pin to LOW.
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_pinMask = 0; // Flag so we know note is no longer playing.
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}
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ISR(TIMER1_COMPA_vect) { // Timer interrupt vector.
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if (millis() >= _nt_time) noNewTone(); // Check to see if it's time for the note to end.
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*_pinOutput ^= _pinMask; // Toggle the pin state.
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} |