jordy morsinkhof / Mbed 2 deprecated Handmatig

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Dependencies:   USBHost USBHostXpad mbed-rtos mbed

Fork of x4180_Tank by C K

Speaker.h@10:7e3987c8fa37, 2015-02-25 (annotated)

Committer:
347467
Date:
Wed Feb 25 08:38:37 2015 +0000
Revision:
10:7e3987c8fa37
Parent:
8:36b2ef26a0b1 
Xboxcontroller;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hotwheelharry 0:79485480cd7e 1 class Speaker
hotwheelharry 0:79485480cd7e 2 {
hotwheelharry 0:79485480cd7e 3 public:
hotwheelharry 0:79485480cd7e 4 Speaker(PinName pin) : _pin(pin) {
hotwheelharry 0:79485480cd7e 5 // _pin(pin) means pass pin to the Speaker Constructor
hotwheelharry 8:36b2ef26a0b1 6 // precompute 64 sample points on one sine wave cycle
hotwheelharry 0:79485480cd7e 7 // used for continuous sine wave output later
hotwheelharry 8:36b2ef26a0b1 8 for(int k=0; k<64; k++) {
hotwheelharry 8:36b2ef26a0b1 9 Analog_out_data[k] = int (65536.0 * ((1.0 + sin((float(k)/64.0*6.28318530717959)))/2.0));
hotwheelharry 0:79485480cd7e 10 // scale the sine wave to 16-bits - as needed for AnalogOut write_u16 arg
hotwheelharry 0:79485480cd7e 11 }
hotwheelharry 0:79485480cd7e 12
hotwheelharry 0:79485480cd7e 13 }
hotwheelharry 0:79485480cd7e 14 // class method to play a note based on AnalogOut class
hotwheelharry 0:79485480cd7e 15 void PlayNote(float frequency, float duration, float volume) {
hotwheelharry 0:79485480cd7e 16 // scale samples using current volume level arg
hotwheelharry 8:36b2ef26a0b1 17 for(int k=0; k<64; k++) {
hotwheelharry 0:79485480cd7e 18 Analog_scaled_data[k] = Analog_out_data[k] * volume;
hotwheelharry 0:79485480cd7e 19 }
hotwheelharry 0:79485480cd7e 20 // reset to start of sample array
hotwheelharry 0:79485480cd7e 21 i=0;
hotwheelharry 0:79485480cd7e 22 // turn on timer interrupts to start sine wave output
hotwheelharry 8:36b2ef26a0b1 23 Sample_Period.attach(this, &Speaker::Sample_timer_interrupt, 1.0/(frequency*64.0));
hotwheelharry 0:79485480cd7e 24 // play note for specified time
hotwheelharry 0:79485480cd7e 25 wait(duration);
hotwheelharry 0:79485480cd7e 26 // turns off timer interrupts
hotwheelharry 0:79485480cd7e 27 Sample_Period.detach();
hotwheelharry 0:79485480cd7e 28 // sets output to mid range - analog zero
hotwheelharry 0:79485480cd7e 29 this->_pin.write_u16(32768);
hotwheelharry 0:79485480cd7e 30
hotwheelharry 0:79485480cd7e 31 }
hotwheelharry 0:79485480cd7e 32 private:
hotwheelharry 0:79485480cd7e 33 // sets up specified pin for analog using AnalogOut class
hotwheelharry 0:79485480cd7e 34 AnalogOut _pin;
hotwheelharry 0:79485480cd7e 35 // set up a timer to be used for sample rate interrupts
hotwheelharry 0:79485480cd7e 36 Ticker Sample_Period;
hotwheelharry 0:79485480cd7e 37
hotwheelharry 0:79485480cd7e 38 //variables used by interrupt routine and PlayNote
hotwheelharry 0:79485480cd7e 39 volatile int i;
hotwheelharry 8:36b2ef26a0b1 40 short unsigned Analog_out_data[64];
hotwheelharry 8:36b2ef26a0b1 41 short unsigned Analog_scaled_data[64];
hotwheelharry 0:79485480cd7e 42
hotwheelharry 0:79485480cd7e 43 // Interrupt routine
hotwheelharry 0:79485480cd7e 44 // used to output next analog sample whenever a timer interrupt occurs
hotwheelharry 0:79485480cd7e 45 void Sample_timer_interrupt(void) {
hotwheelharry 0:79485480cd7e 46 // send next analog sample out to D to A
hotwheelharry 0:79485480cd7e 47 this->_pin.write_u16(Analog_scaled_data[i]);
hotwheelharry 8:36b2ef26a0b1 48 // increment pointer and wrap around back to 0 at 64
hotwheelharry 8:36b2ef26a0b1 49 i = (i+1) & 0x03F;
hotwheelharry 0:79485480cd7e 50 }
hotwheelharry 0:79485480cd7e 51 };
hotwheelharry 0:79485480cd7e 52