Kevin Jones / Mbed 2 deprecated MIDISynthwithSpecAnalyzer

A synthesizer that is controlled by a USB MIDI Keyboard. Also displays corresponding frequencies via a simple spectrum analyzer on a LCD. Uses a watchdog timer to reset Mbed in case it freezes.

Dependencies:   4DGL-uLCD-SE USBHostMIDI mbed

Fork of USBHostMIDI_example by Kaoru Shoji

MIDISpeaker.h@3:d48372c1347e, 2017-12-13 (annotated)

Committer:
kjones99
Date:
Wed Dec 13 17:17:07 2017 +0000
Revision:
3:d48372c1347e
Parent:
2:5366ce17fe55 
Final version with comments.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kjones99 2:5366ce17fe55 1 #include "mbed.h"
kjones99 2:5366ce17fe55 2 #include "uLCD_4DGL.h"
kjones99 2:5366ce17fe55 3
kjones99 2:5366ce17fe55 4 #define BAUD_9600 312
kjones99 2:5366ce17fe55 5 // new class to play a note on Speaker based on PwmOut class
kjones99 2:5366ce17fe55 6 uLCD_4DGL uLCD(p9,p10,p11);
kjones99 2:5366ce17fe55 7 int x1;
kjones99 2:5366ce17fe55 8 int y1;
kjones99 2:5366ce17fe55 9 class MIDISpeaker
kjones99 2:5366ce17fe55 10 {
kjones99 2:5366ce17fe55 11 public:
kjones99 2:5366ce17fe55 12 MIDISpeaker(PinName pin) : _pin(pin) {
kjones99 2:5366ce17fe55 13 // _pin(pin) means pass pin to the Speaker Constructor
kjones99 2:5366ce17fe55 14 }
kjones99 2:5366ce17fe55 15 // class method to play a note based on PwmOut class
kjones99 2:5366ce17fe55 16 void PlayNote(unsigned char note, unsigned char velocity) {//volatile int duration) {
kjones99 2:5366ce17fe55 17 int notef = int(note); //convert note to int
kjones99 2:5366ce17fe55 18 int velocityf = int(velocity); //convert velocity to int
kjones99 2:5366ce17fe55 19 double noteg = double(notef); //convert note to double
kjones99 2:5366ce17fe55 20 double velocityg = double(velocityf); //convert velocity to double
kjones99 2:5366ce17fe55 21 double f_n = double((noteg - 49)/12); //use piano frequency formula to find corresponding frequency
kjones99 2:5366ce17fe55 22 double freq = (pow(2, f_n)) * 440;
kjones99 2:5366ce17fe55 23 _pin.period(1.0/freq); //use frequency to set period of pwmout pin
kjones99 2:5366ce17fe55 24 velocityg = ((velocityg/127.0) * 0.5); //calculate volume of note and set to pwmout pin
kjones99 2:5366ce17fe55 25 _pin = velocityg;
kjones99 2:5366ce17fe55 26 x1 = ((freq/4000)*115) + 5; //calcuate starting position for frequency spectrum [0,4000 Hz]
kjones99 2:5366ce17fe55 27 y1 = 110 - ((_pin/0.5)*105); // calculate magnitude of spectrum based on velocity
kjones99 2:5366ce17fe55 28 uLCD.locate(0,13);
kjones99 2:5366ce17fe55 29 uLCD.printf("\nkey: %d, freq: %4.0f, volume: %.2f\n", note, freq, velocityg);
kjones99 2:5366ce17fe55 30 uLCD.textbackground_color(BLUE);
kjones99 2:5366ce17fe55 31 uLCD.filled_rectangle(x1, y1, x1+2, 109, BLACK);
kjones99 2:5366ce17fe55 32 }
kjones99 2:5366ce17fe55 33 void StopNote() {
kjones99 2:5366ce17fe55 34 _pin = 0.0;
kjones99 2:5366ce17fe55 35 //uLCD.filled_rectangle(x1, y1, x1+2, 109, BLUE); //code to clear rectangle from lcd
kjones99 2:5366ce17fe55 36 }
kjones99 2:5366ce17fe55 37
kjones99 2:5366ce17fe55 38 private:
kjones99 2:5366ce17fe55 39 // sets up specified pin for PWM using PwmOut class
kjones99 2:5366ce17fe55 40 PwmOut _pin;
kjones99 2:5366ce17fe55 41 };
kjones99 2:5366ce17fe55 42
kjones99 2:5366ce17fe55 43 // Speaker test program - earlier euro police style siren now using new class method
kjones99 2:5366ce17fe55 44 //