File content as of revision 6:7985a531acb9:

/* ECE4180 Final Project -- mbed Function Generator
    
   Platform: mbed LPC-1768
    
   Team member: Hanjie Xie
                Qiuyang Tao
                Xuefeng Jin
                Yuqing Peng
*/


#include "mbed.h"
#include "uLCD_4DGL.h"

//----- Objects for devices----------------------
Serial pc(USBTX, USBRX);
uLCD_4DGL lcd(p13, p14, p15);
AnalogOut  aout(p18);
DigitalOut dout(LED1);

//
Ticker output_trigger;
DigitalOut led1(LED1);

//-----Global variable used for Func_Gen---------
const double pi = 3.14;
float time_interv;
int datapoint_counter=0;
int length_waveform=100;
uint16_t waveform[10];
float x;

//-----User Specified, change it if needed-------
int waveform_type; //0 for sine, 
float freq,amp,offset,duty_cycle; 

/*
  sine wave use: freq,amp,offset
  square wave use: freq,amp,offse and duty_cycle
*/


void initialize_LCD(){
    lcd.baudrate(3000000);
    lcd.background_color(0);
    lcd.cls();
    
    lcd.printf("Initializing...\n");
    lcd.printf("Fun Generator Demo"); 
}

void generate_waveform_datapoints(){ //Generate data points for the waveform
    float t=0;
     
    //------if sine wave--------
    if (waveform_type==0){  
        for (int counter=0; counter<length_waveform; counter++){
            x=amp/3.3*cos(2*pi*freq*t)+offset/3.3;
            waveform[counter]=(uint16_t) (x*65535);      
            t += time_interv;
        }
    }
    
    //------if square wave--------   
    if (waveform_type==1){  
        for (int counter=0; counter<length_waveform; counter++){
            if (counter<=length_waveform*duty_cycle){
                x=amp/3.3+offset/3.3;
            }else{
                x=-1.0*amp/3.3+offset/3.3;
            }
            waveform[counter]=(uint16_t) (x*65535);   
        }           
    }
    
    //------if triangle wave---------  
    if (waveform_type==2){  
        for (int counter=0; counter<length_waveform; counter++){
            if (counter<=length_waveform*duty_cycle){
                x=amp/3.3+offset/3.3;
            }else{
                x=-1.0*amp/3.3+offset/3.3;
            }
            waveform[counter]=(uint16_t) (x*65535);   
        }           
    }
}



void output_waveform_datapoints(){  //Output the data points using DAC (pin18)
    for (int counter=0; counter<length_waveform; counter++){
        aout.write_u16(waveform[counter]);
        wait(time_interv);
    } 
}


void output_waveform_datapoints_timer_ISR(){  //Output the data points using DAC (pin18)
        aout.write_u16(waveform[datapoint_counter]);
        datapoint_counter++;
        
        if (datapoint_counter==length_waveform-1){datapoint_counter=0;}
}


 
int main(void){
    waveform_type=1; //0 for sine, 
    freq=100; //Hz
    amp=0.5; //Sacle factor, 1=full range
    offset=0.5;
    duty_cycle=0.4;
    
    time_interv=1.0/freq/length_waveform;
    
    
    initialize_LCD();
    generate_waveform_datapoints();
    
    
    //-----output waveform--------
    output_trigger.attach(&output_waveform_datapoints_timer_ISR, time_interv);
    while (1){
    //    output_waveform_datapoints();
    }
}