am_radio.h

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/**
 * @file am_radio.h
 * @ingroup am_radio
 * @author Jason Duffy
 * @date 10th September 2022
 * @brief Driver for a small, low power AM radio transmitter, to broadcast
 * monophonic square wave tones over a short distance. This project was
 * inspired by the book "Make: AVR Programming" by Elliot Williams. 
 * 
 * Only tested with F_CPU = 8MHZ, but will build on this later to make it work
 * with other CPU speeds. 
 */
 
#ifndef AM_RADIO_DOT_H
#define AM_RADIO_DOT_H
 
#include <stdint.h>
#include "scale.h"
 
 
/**
 * Enum to expose the predefined carrier frequency options.
 * 1000KHZ (1MHZ) is ideal, but may be taken in your locality so try another if
 * there is too much interferance. 
 */
typedef enum
{   
    _500_KHZ = 500000,
    _570_KHZ = 570000,
    _670_KHZ = 670000,
    _800_KHZ = 800000,
    _1000_KHZ = 1000000,
    _1333_KHZ = 1333000,
}frequency_khz_t;
 
 
/**
 * Enum to expose the predefined duration options. 
 */
typedef enum
{
    SEMIBREVE,
    MINIM,
    CROTCHET,
    QUAVER,
    SEMIQUAVER,
    DEMISEMIQUAVER,
}note_duration_t;
 
 
/**
 * Initialises timer/counter for radio transmission at a specified carrier frequency.
 */
void init_am_radio(frequency_khz_t carrier_freq);
 
/**
 * Sets tempo for musical tones to be transmitted (in BPM).
 */
void am_radio_set_tempo(uint8_t tempo);
 
/**
 * Transmits a square wave, monophonic note for the specified duration.
 */
void am_radio_transmit_note(note_pitch_t pitch, note_duration_t note_length);
 
/**
 * Waits a specified duration before playing the next note. 
 */
void am_radio_rest(note_duration_t rest_length);
 
/**
 * Test sequence, transmits an arpeggio scale in C major. 
 */
void arpeggio_in_c_test(void);
 
 
#endif //AM_RADIO_DOT_H
 
/*** end of file ***/