// Squawk Soft-Synthesizer Library for Arduino // // Davey Taylor 2013 // d.taylor@arduino.cc #ifndef _SQUAWK_H_ #define _SQUAWK_H_ #include #include #include "Arduino.h" #define Melody const uint8_t PROGMEM class SquawkStream { public: virtual ~SquawkStream() = 0; virtual uint8_t read() = 0; virtual void seek(size_t offset) = 0; }; inline SquawkStream::~SquawkStream() { } class SquawkSynth { protected: // Load and play specified melody void play(SquawkStream *melody); public: SquawkSynth() {}; // Initialize Squawk to generate samples at sample_rate Hz void begin(uint16_t sample_rate); // Load and play specified melody // melody needs to point to PROGMEM data void play(const uint8_t *melody); // Resume currently loaded melody (or enable direct osc manipulation by sketch) void play(); // Pause playback void pause(); // Stop playback (unloads song) void stop(); // Tune Squawk to a different frequency - default is 1.0 void tune(float tuning); // Change the tempo - default is 50 void tempo(uint16_t tempo); }; extern SquawkSynth Squawk; // oscillator structure typedef struct { uint8_t vol; uint16_t freq; uint16_t phase; } osc_t; typedef osc_t Oscillator; // oscillator memory extern osc_t osc[4]; extern uint8_t pcm; // channel 0 is pulse wave @ 25% duty // channel 1 is square wave // channel 2 is triangle wave // channel 3 is noise // For channel 3, freq is used as part of its LFSR and should not be changed. // LFSR: Linear feedback shift register, a method of producing a // pseudo-random bit sequence, used to generate nasty noise. #ifdef __AVR_ATmega32U4__ // Supported configurations for ATmega32U4 #define SQUAWK_PWM_PIN5 OCR3AL #define SQUAWK_PWM_PIN11 OCR0A #define SQUAWK_PWM_PIN3 OCR0B /* // NOT SUPPORTED YET #define SQUAWK_PWM_PIN6 OCR4D #define SQUAWK_PWM_PIN9 OCR4B #define SQUAWK_PWM_PIN10 OCR4B */ #endif #ifdef __AVR_ATmega168__ // Supported configurations for ATmega168 #define SQUAWK_PWM_PIN6 OCR0A #define SQUAWK_PWM_PIN5 OCR0B #define SQUAWK_PWM_PIN11 OCR2A #define SQUAWK_PWM_PIN3 OCR2B #endif #ifdef __AVR_ATmega328P__ // Supported configurations for ATmega328P #define SQUAWK_PWM_PIN6 OCR0A #define SQUAWK_PWM_PIN5 OCR0B #define SQUAWK_PWM_PIN11 OCR2A #define SQUAWK_PWM_PIN3 OCR2B #endif /* // NOT SUPPORTED YET #define SQUAWK_SPI SPDR #define SQUAWK_RLD_PORTB PORTB #define SQUAWK_RLD_PORTC PORTC */ extern void squawk_playroutine() asm("squawk_playroutine"); // SAMPLE GRINDER // generates samples and updates oscillators // uses 132 cycles (not counting playroutine) // ~1/3 CPU @ 44kHz on 16MHz #define SQUAWK_CONSTRUCT_ISR(TARGET_REGISTER) \ __attribute__((used)) uint16_t cia, cia_count; \ intptr_t squawk_register = (intptr_t)&TARGET_REGISTER; \ ISR(TIMER1_COMPA_vect, ISR_NAKED) { \ asm volatile( \ "push r2 " "\n\t" \ "in r2, __SREG__ " "\n\t" \ "push r18 " "\n\t" \ "push r27 " "\n\t" \ "push r26 " "\n\t" \ "push r0 " "\n\t" \ "push r1 " "\n\t" \ \ "lds r18, osc+2*%[mul]+%[fre] " "\n\t" \ "lds r0, osc+2*%[mul]+%[pha] " "\n\t" \ "add r0, r18 " "\n\t" \ "sts osc+2*%[mul]+%[pha], r0 " "\n\t" \ "lds r18, osc+2*%[mul]+%[fre]+1" "\n\t" \ "lds r1, osc+2*%[mul]+%[pha]+1" "\n\t" \ "adc r1, r18 " "\n\t" \ "sts osc+2*%[mul]+%[pha]+1, r1 " "\n\t" \ \ "mov r27, r1 " "\n\t" \ "sbrc r27, 7 " "\n\t" \ "com r27 " "\n\t" \ "lsl r27 " "\n\t" \ "lds r26, osc+2*%[mul]+%[vol] " "\n\t" \ "subi r27, 128 " "\n\t" \ "muls r27, r26 " "\n\t" \ "lsl r1 " "\n\t" \ "mov r26, r1 " "\n\t" \ \ "lds r18, osc+0*%[mul]+%[fre] " "\n\t" \ "lds r0, osc+0*%[mul]+%[pha] " "\n\t" \ "add r0, r18 " "\n\t" \ "sts osc+0*%[mul]+%[pha], r0 " "\n\t" \ "lds r18, osc+0*%[mul]+%[fre]+1" "\n\t" \ "lds r1, osc+0*%[mul]+%[pha]+1" "\n\t" \ "adc r1, r18 " "\n\t" \ "sts osc+0*%[mul]+%[pha]+1, r1 " "\n\t" \ \ "mov r18, r1 " "\n\t" \ "lsl r18 " "\n\t" \ "and r18, r1 " "\n\t" \ "lds r27, osc+0*%[mul]+%[vol] " "\n\t" \ "sbrc r18, 7 " "\n\t" \ "neg r27 " "\n\t" \ "add r26, r27 " "\n\t" \ \ "lds r18, osc+1*%[mul]+%[fre] " "\n\t" \ "lds r0, osc+1*%[mul]+%[pha] " "\n\t" \ "add r0, r18 " "\n\t" \ "sts osc+1*%[mul]+%[pha], r0 " "\n\t" \ "lds r18, osc+1*%[mul]+%[fre]+1" "\n\t" \ "lds r1, osc+1*%[mul]+%[pha]+1" "\n\t" \ "adc r1, r18 " "\n\t" \ "sts osc+1*%[mul]+%[pha]+1, r1 " "\n\t" \ \ "lds r27, osc+1*%[mul]+%[vol] " "\n\t" \ "sbrc r1, 7 " "\n\t" \ "neg r27 " "\n\t" \ "add r26, r27 " "\n\t" \ \ "ldi r27, 1 " "\n\t" \ "lds r0, osc+3*%[mul]+%[fre] " "\n\t" \ "lds r1, osc+3*%[mul]+%[fre]+1" "\n\t" \ "add r0, r0 " "\n\t" \ "adc r1, r1 " "\n\t" \ "sbrc r1, 7 " "\n\t" \ "eor r0, r27 " "\n\t" \ "sbrc r1, 6 " "\n\t" \ "eor r0, r27 " "\n\t" \ "sts osc+3*%[mul]+%[fre], r0 " "\n\t" \ "sts osc+3*%[mul]+%[fre]+1, r1 " "\n\t" \ \ "lds r27, osc+3*%[mul]+%[vol] " "\n\t" \ "sbrc r1, 7 " "\n\t" \ "neg r27 " "\n\t" \ "add r26, r27 " "\n\t" \ \ "lds r27, pcm " "\n\t" \ "add r26, r27 " "\n\t" \ "sts %[reg], r26 " "\n\t" \ \ "lds r27, cia_count+1 " "\n\t" \ "lds r26, cia_count " "\n\t" \ "sbiw r26, 1 " "\n\t" \ "breq call_playroutine " "\n\t" \ "sts cia_count+1, r27 " "\n\t" \ "sts cia_count, r26 " "\n\t" \ "pop r1 " "\n\t" \ "pop r0 " "\n\t" \ "pop r26 " "\n\t" \ "pop r27 " "\n\t" \ "pop r18 " "\n\t" \ "out __SREG__, r2 " "\n\t" \ "pop r2 " "\n\t" \ "reti " "\n\t" \ "call_playroutine: " "\n\t" \ \ "lds r27, cia+1 " "\n\t" \ "lds r26, cia " "\n\t" \ "sts cia_count+1, r27 " "\n\t" \ "sts cia_count, r26 " "\n\t" \ \ "sei " "\n\t" \ "push r19 " "\n\t" \ "push r20 " "\n\t" \ "push r21 " "\n\t" \ "push r22 " "\n\t" \ "push r23 " "\n\t" \ "push r24 " "\n\t" \ "push r25 " "\n\t" \ "push r30 " "\n\t" \ "push r31 " "\n\t" \ \ "clr r1 " "\n\t" \ "call squawk_playroutine " "\n\t" \ \ "pop r31 " "\n\t" \ "pop r30 " "\n\t" \ "pop r25 " "\n\t" \ "pop r24 " "\n\t" \ "pop r23 " "\n\t" \ "pop r22 " "\n\t" \ "pop r21 " "\n\t" \ "pop r20 " "\n\t" \ "pop r19 " "\n\t" \ \ "pop r1 " "\n\t" \ "pop r0 " "\n\t" \ "pop r26 " "\n\t" \ "pop r27 " "\n\t" \ "pop r18 " "\n\t" \ "out __SREG__, r2 " "\n\t" \ "pop r2 " "\n\t" \ "reti " "\n\t" \ : \ : [reg] "M" _SFR_MEM_ADDR(TARGET_REGISTER), \ [mul] "M" (sizeof(Oscillator)), \ [pha] "M" (offsetof(Oscillator, phase)), \ [fre] "M" (offsetof(Oscillator, freq)), \ [vol] "M" (offsetof(Oscillator, vol)) \ ); \ } #endif