Curtis Mattull / Mbed 2 deprecated function_generator

using LUT generate sine, square, triangle wave with variable freq

Dependencies:   mbed-dsp mbed

main.cpp@0:4a2e0ba6c332, 2016-11-08 (annotated)

Committer:
cpm219
Date:
Tue Nov 08 01:14:27 2016 +0000
Revision:
0:4a2e0ba6c332
latest version

Who changed what in which revision?

UserRevisionLine numberNew contents of line
cpm219 0:4a2e0ba6c332 1 /*
cpm219 0:4a2e0ba6c332 2 function generator
cpm219 0:4a2e0ba6c332 3 Curtis Mattull
cpm219 0:4a2e0ba6c332 4 10/14/16
cpm219 0:4a2e0ba6c332 5 */
cpm219 0:4a2e0ba6c332 6 #include "mbed.h"
cpm219 0:4a2e0ba6c332 7 #include "arm_math.h"
cpm219 0:4a2e0ba6c332 8 #include "arm_const_structs.h"
cpm219 0:4a2e0ba6c332 9 #include "my_LUT.h"
cpm219 0:4a2e0ba6c332 10
cpm219 0:4a2e0ba6c332 11 void inc_func(void);
cpm219 0:4a2e0ba6c332 12 void inc_freq(void);
cpm219 0:4a2e0ba6c332 13
cpm219 0:4a2e0ba6c332 14 AnalogOut vout(DAC0_OUT);
cpm219 0:4a2e0ba6c332 15 Serial pc(USBTX,USBRX);
cpm219 0:4a2e0ba6c332 16
cpm219 0:4a2e0ba6c332 17 InterruptIn sw2(SW2);
cpm219 0:4a2e0ba6c332 18 InterruptIn sw3(SW3);
cpm219 0:4a2e0ba6c332 19
cpm219 0:4a2e0ba6c332 20
cpm219 0:4a2e0ba6c332 21 const int num_pts = 128;
cpm219 0:4a2e0ba6c332 22 double desired_freq = 60; //60 Hz
cpm219 0:4a2e0ba6c332 23 int func = 0;
cpm219 0:4a2e0ba6c332 24 double dt = (1/desired_freq)/num_pts; // 1/60 = 0.0167, dt = 0.0167/num_pts
cpm219 0:4a2e0ba6c332 25 const double dac_write_delay = 0.000009;
cpm219 0:4a2e0ba6c332 26 double sample_delay = dt-dac_write_delay;
cpm219 0:4a2e0ba6c332 27
cpm219 0:4a2e0ba6c332 28 int main(void)
cpm219 0:4a2e0ba6c332 29 {
cpm219 0:4a2e0ba6c332 30 pc.baud(115200);
cpm219 0:4a2e0ba6c332 31 pc.printf("start\r\n");
cpm219 0:4a2e0ba6c332 32
cpm219 0:4a2e0ba6c332 33 int i =0;
cpm219 0:4a2e0ba6c332 34 double amplitude = 0.5;
cpm219 0:4a2e0ba6c332 35 // static float write_dac_time = 0;
cpm219 0:4a2e0ba6c332 36 // static Timer timer;
cpm219 0:4a2e0ba6c332 37 // static float begin = 0,
cpm219 0:4a2e0ba6c332 38 // end = 0;
cpm219 0:4a2e0ba6c332 39 sw2.rise(&inc_func);
cpm219 0:4a2e0ba6c332 40 sw3.rise(&inc_freq);
cpm219 0:4a2e0ba6c332 41
cpm219 0:4a2e0ba6c332 42 // timer.start();
cpm219 0:4a2e0ba6c332 43 // begin = timer.read_us();
cpm219 0:4a2e0ba6c332 44 // vout.write(amplitude+.5*LUT[func][i*(int)(512/num_pts)]);
cpm219 0:4a2e0ba6c332 45 // timer.stop();
cpm219 0:4a2e0ba6c332 46 // end = timer.read_us(); //trigger_end
cpm219 0:4a2e0ba6c332 47 // write_dac_time = end-begin;
cpm219 0:4a2e0ba6c332 48 //
cpm219 0:4a2e0ba6c332 49 // pc.printf("dac write time[us]: %f", write_dac_time);
cpm219 0:4a2e0ba6c332 50 // wait(1);
cpm219 0:4a2e0ba6c332 51
cpm219 0:4a2e0ba6c332 52 while(1) {
cpm219 0:4a2e0ba6c332 53 /*populate some dummy sin data*/
cpm219 0:4a2e0ba6c332 54 for(i = 0; i< num_pts; i++)
cpm219 0:4a2e0ba6c332 55 {//dac write time was determined to be 8us
cpm219 0:4a2e0ba6c332 56 vout.write(amplitude+.5*LUT[func][i*(int)(512/num_pts)]);
cpm219 0:4a2e0ba6c332 57 wait(sample_delay);
cpm219 0:4a2e0ba6c332 58 }
cpm219 0:4a2e0ba6c332 59 }
cpm219 0:4a2e0ba6c332 60 }
cpm219 0:4a2e0ba6c332 61
cpm219 0:4a2e0ba6c332 62 void inc_func(void)
cpm219 0:4a2e0ba6c332 63 {
cpm219 0:4a2e0ba6c332 64 func++;
cpm219 0:4a2e0ba6c332 65 if (func==3)
cpm219 0:4a2e0ba6c332 66 {
cpm219 0:4a2e0ba6c332 67 func = 0;
cpm219 0:4a2e0ba6c332 68 }
cpm219 0:4a2e0ba6c332 69 }
cpm219 0:4a2e0ba6c332 70
cpm219 0:4a2e0ba6c332 71 void inc_freq(void)
cpm219 0:4a2e0ba6c332 72 {
cpm219 0:4a2e0ba6c332 73 desired_freq++;
cpm219 0:4a2e0ba6c332 74 if (desired_freq>200)
cpm219 0:4a2e0ba6c332 75 {
cpm219 0:4a2e0ba6c332 76 desired_freq =1;
cpm219 0:4a2e0ba6c332 77 }
cpm219 0:4a2e0ba6c332 78 dt = (1/desired_freq)/num_pts; // 1/60 = 0.0167, dt = 0.0167/num_pts
cpm219 0:4a2e0ba6c332 79 sample_delay = dt-dac_write_delay;
cpm219 0:4a2e0ba6c332 80
cpm219 0:4a2e0ba6c332 81 }