File content as of revision 4:9b7ea5528a5c:

/*
ELEC2645 Embedded Systems Project
School of Electronic & Electrical Engineering
University of Leeds
2019/20

Name: Luke Cartwright
Username: el18loc
Student ID Number: 201225242
Start Date: 06/02/2020
Last Edited: 07/04/2020
*/

// Includes
#include "mbed.h"
#include "Gamepad.h"
#include "N5110.h"

// Objects
Gamepad pad;
N5110 lcd;
Ticker down;
Ticker period;

DigitalOut rca(PTC4);

Serial pc(USBTX, USBRX);

//Functions
void startup();
void squareWave();
void wavetable();
//void sinspeak();
void down_isr();
void up_isr();

//Arrays for startup
const char CART[4] = {'C','A','R','T'};

//Global Variables
volatile double wavtable[4096]; //Wavetable array
// all times drastically slowed to attempt debugging in teraterm
float g_period = 0.002;
float g_unused= g_period*1000000.0f;
int g_period_us=g_unused;
volatile uint64_t g_uptime_us = g_period_us/2; // placeholder value
//isr interrupt flags
volatile int g_upflag=1;
volatile int g_downflag=1;

int main()
{
    printf("RUNNING CODE \n");
    startup(); //initialises board and displays start screen
    wavetable(); //generates wavtable array
    //pad.leds_on();
    squareWave(); //generates pulse wave modulated by sin wave
    //pad.leds_off();
    //sinspeak();
}


void startup()
{
    pad.init(); //initiate Gamepad
    pad.leds_on(); //turn LEDS on to show starting up
    printf("Initialising Pad\n");
    lcd.init(); //intitates screen
    lcd.clear();
    lcd.setContrast(0.5); //contrast setting
    lcd.inverseMode(); //puts screen in -ve
    //position for CART
    const int x = 10;
    const int y = 2;
    //Prints CART SYNTH to display
    lcd.printString(CART,x,y);
    lcd.refresh();
    wait_ms(1800); //timer to allow theme to play out
    lcd.clear();
    lcd.refresh(); //sets clear screen
    pad.leds_off(); //turns of leds to show ready
}


void wavetable()
{
    double sin_d[4096];

    pad.leds_on(); //shows computating (debug)
    printf("Generating Wavetable \n");

    for (int i=0; i<4096; i++) {
        sin_d[i] = 0.5f*sin(2.0f*PI*(i/4096.0f));
        wavtable[i]= sin_d[i]+0.5; //generates wave table 0<1 in double
        //printf("wav[i]= %f \n", wavtable[i]); // Used for Debug
    }
    pad.leds_off();
}


void squareWave()
{
    printf("Generating SIN PWM \n");

    int i=0; //int based iterator
    float ifl=0; //float based itterator
    float f=50; //frequency of sin wave produced
    period.attach_us(&up_isr,g_period_us); //ticker to write 1 to rca
    down.attach_us(&down_isr,g_uptime_us); //ticker to write 0 to rca
    
    
    printf("g_period_us: %d \n", g_period_us);
    printf("sin Frequency: %f \n", f);

    while (1) { //continual loop for pulse production
        float dutyratio = wavtable[i]; //calcualtes duty ratio of pulse
        
        g_uptime_us= dutyratio*g_period_us; //calculates duty ratio in usecs
        if (g_uptime_us<1) {
            g_uptime_us=g_period_us/100;
            } //sets to be value for timebeing to eliminate 0 error
        //float f=440*(pad.read_pot1()+1); //removed for simplification
        
        if (g_upflag==0) {
            
            ifl = ifl + (4096*f*g_period); //once rca=1 itterate sin function
            if (ifl>4096) {
                ifl= ifl-4096;
                }
            i=ifl;
            
            g_upflag=1; //reset flag
            //printf("iterate i: i= %d, ifl= %f \n", i, ifl);
        }
        
        //printf("DR: %f \n",dutyratio);
        //printf("sleep \n");
        sleep(); //sleeps till next isr
    }
}

void down_isr() //sets rca to 0
{
    //printf("downISR \n");
    if (g_downflag==0) {//stops error trigger
        rca.write(0);
        g_downflag=1;
        g_uptime_us= g_uptime_us+g_period_us; // eliminates it calling if =0
        //printf("0 \n");//print only in while v. slow freguency
    }
}

void up_isr() //sets rca=1
{
    //printf("upISR \n");
    rca.write(1);
    down.attach_us(&down_isr,g_uptime_us); //timer to set rca=0 after elapsed
    g_upflag=0; //sets flag to iterate
    g_downflag=0; //sets flag to allow set to 0
    //printf("1 \n"); //only in while at v low frequency
}


/*
void sinspeak ()
{
    float f1=440.0;
    float i=0;
    unsigned short v=0;
    int inc=0;
    pad.reset_buttons();
    f1 = pad.read_pot1();
    f1 = 440.0f+440.0f*f1;
    //printf("f1= %f \n",f1); // Used for Debug

    while (inc<3000) {
        int inti = i;
        v = o[inti];
        printf("OUTPUT: %u \n", v);
        //pad.write_u16(v);
        wait_us(230); //fs= 4k Ts=250us

        i = i + ((4096.0f*f1)/4000.0f); //i+((samples*f)*Ts)
        if (i>=4096.0f) {
            i=i-4096.0f;
        }
        else {
            wait_us(3); // used to attempt note stabilisation to match other loop
            }
        inc++;
    }
}
*/