| Mozzi version v1.1.0 sound synthesis library for Arduino |

AudioConfigHiSpeed14bitPwm.h
1 #ifndef AUDIOCONFIGHISPEED14BITPWM_H
2 #define AUDIOCONFIGHISPEED14BITPWM_H
3
4 /*
5 14 bit sound at 16384 Hz and 125kHz pwm rate
6 Timer 1: PWM 125kHz
7 Timer 2: called at AUDIO_RATE 16384 Hz, setting Timer1 pwm levels
8 Output on Timer1, low uint8_t on Pin 10, and high uint8_t on Pin 9 (on 328 based Arduino boards)
9 Add signals through a 3.9k resistor on high uint8_t pin and 499k resistor on low uint8_t pin.
10 Use 0.5% resistors or select the most accurate from a batch.
11 As discussed on http://www.openmusiclabs.com/learning/digital/pwm-dac/dual-pwm-circuits/
12 Also, there are higher quality output circuits are on the site.
13
14 Boards, pins and resistor positions are documented in MozziGuts.h
15 */
16
17 /* PWM carrier frequency, for HIFI this should be well out of hearing range, about 5 times the nyquist frequency if possible. */
18 #define PWM_RATE 125000
19 // following doesn't play nice
20 //#define PWM_RATE 65536 // count will be 244 (7+ bits) on each pin = 14+ bits
21
22
23 // pins defined in TimerOne/config/known_16bit_timers.h
24 #define AUDIO_CHANNEL_1_highByte_PIN TIMER1_A_PIN // 3.9k resistor
25 #define AUDIO_CHANNEL_1_lowByte_PIN TIMER1_B_PIN // 499k resistor
26 #define AUDIO_CHANNEL_1_highByte_REGISTER OCR1AL
27 #define AUDIO_CHANNEL_1_lowByte_REGISTER OCR1BL
28
29 #define AUDIO_BITS_PER_REGISTER 7
30
31 /* Used internally to put the 0-biased generated audio into the right range for PWM output.*/
32 // 14 bit
33 #define AUDIO_BIAS ((unsigned int) 0x2000)
34
35
36 #endif // #ifndef AUDIOCONFIGHISPEED14BITPWM_H