common.h

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/*
We have a 40 kHz or 50 kHz timer interrupt that handles sound
samples. First it writes the previously computed sample to the serial DAC.
Then it computes the sample for the next time.
*/

#ifndef COMMON_H_INCLUDED
#define COMMON_H_INCLUDED 1

#ifndef __STDINT
#include <stdint.h>
#define __STDINT 1
#endif

#ifndef __ARDUINO
#define __ARDUINO 1
#endif

#ifndef ASSERT
#define ASSERT(cond)    ((void*) 0)
#endif

#ifndef NULL
#define NULL   0
#endif

#define SAMPLING_RATE   40000
#define DT (1.0 / SAMPLING_RATE)

#define NUM_KEYS 16   // 17? 34? 40?
#define NUM_VOICE_BITS 3
#define NUM_VOICES (1 << NUM_VOICE_BITS)

// This is for a 330K resistor.
#define THRESHOLD 12

#define KEYDOWN_COUNT 5

class Key;
extern Key *keyboard[NUM_KEYS];
class Voice;
extern Voice v[NUM_VOICES];

extern int32_t mult_signed(int32_t x, int32_t y);
extern int32_t mult_unsigned(uint32_t x, uint32_t y);
extern int32_t mult_unsigned_signed(uint32_t x, int32_t y);

#endif     // COMMON_H_INCLUDED