Diff: Encoder.cpp

Revision:

0:57a56e69e3cc

diff -r 000000000000 -r 57a56e69e3cc Encoder.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Encoder.cpp	Tue Mar 22 15:30:43 2016 +0000
@@ -0,0 +1,122 @@
+#include "mbed.h"
+#include "Motor.h"
+#include "QEI.h"
+
+// Definitions
+#define PI           (3.1415926)
+#define LOG_FREQ     (100)      // (Hz) - data logging frequency
+#define NUM_DATA_PTS (500)      // (#)  - number of data points at above LOG_FREQ;
+
+// Classes and objects
+QEI        enc(p17,p16,NC,1600); // Need to know PPR count of selected encoder
+Serial     pc(USBTX, USBRX);
+Motor m(p22,p21,p23); // pin 18 will not be used
+Timer      t;
+Ticker     ticker_timer;
+DigitalOut mbed_LED(LED1);
+
+// Create local file system under the name "mBed_drive"
+LocalFileSystem mBed_drive("local");
+
+// Global declarations
+int   num_data_pts_rec, i;
+char  c;
+float theta;
+float lv_time[NUM_DATA_PTS];
+float lv_theta[NUM_DATA_PTS];
+
+
+// timer_function
+void timer_function()
+{
+
+//generate random data
+//float min = 0.1 / 3.3;  //Define 0.1 V as ~03% from 3.3 V
+//float max = 3.2 / 3.3;  //Define 3.2 V as ~97% from 3.3 V
+
+//measure signal
+//signal = min + ((float)rand()/RAND_MAX)*(max - min)*3.3;  // Generate random voltage output from 0.1 to 3.2
+//printf("Voltage= %1.2f \n", signal);     // Debug
+
+// Measure theta
+    theta = (long)enc.getPulses()/(1600.0*2.0)*2.0*PI;  // The QEI uses 2X interpolation by default.
+    if(num_data_pts_rec<NUM_DATA_PTS) {
+        lv_time[num_data_pts_rec]  = t.read();
+        lv_theta[num_data_pts_rec] = theta;
+        num_data_pts_rec++;
+    }
+}
+
+// main function
+int main()
+{
+    // Serial port initializations
+    pc.baud(9600);
+
+    // Initialize encoder
+    enc.reset();
+
+    // Number of data points recorded
+    num_data_pts_rec = 0;
+
+    // Clear Terra Term screen
+    for(i=1; i<80; i++)
+        pc.printf("\n\r");
+
+    // Prompt user to start recording data.
+    pc.printf("Running datalog.cpp.\r\n");
+    pc.printf("____________________________________________________________r\n");
+    pc.printf("\r\nPress any key to start.\r\n");
+
+    // Wait until user presses a key
+    while(!pc.readable());
+    c = pc.getc();
+    c = '\0';
+
+    // Start timer and tickers
+    t.start();
+    ticker_timer.attach(&timer_function,1.0/LOG_FREQ);
+
+    // Measurement while loop
+    while(num_data_pts_rec < NUM_DATA_PTS) {
+        // Print data to screen
+        pc.printf("%.2f %.2f; \n\r",t.read(),theta);
+    }
+
+    // Turn off ticker functions
+    ticker_timer.detach();
+
+    // File initialization
+    pc.printf("Opening mBed_output.m                ... ");
+    FILE *fp = fopen("/local/mBedOut.m", "w");
+    pc.printf("done.\n");
+
+    // Print measured data to local file.
+    pc.printf("Printing measured data to local file ... ");
+    fprintf(fp,"lv.time = [  \n");
+    for(i=0; i<num_data_pts_rec; i++) {
+        //fprintf(fp,"lv.time(%d,1) = [ %.5f;\n",i+1,lv_time[i]);
+        fprintf(fp, "%.5f; \n",lv_time[i]);
+    }
+    fprintf(fp,"]; \n");
+    fprintf(fp,"lv.theta = [  \n");
+    for(i=0; i<num_data_pts_rec; i++) {
+        fprintf(fp,"%.5f;\n",lv_theta[i]);
+    }
+    fprintf(fp,"]; \n");
+    fprintf(fp,"plot(lv.time,lv.theta); \n");
+    fprintf(fp,"xlabel('time (s)'); \n");
+    fprintf(fp,"ylabel('radians'); \n");
+
+    //fprintf(fp,"lv.units = '(volts)';");
+    pc.printf("done.\n\r");
+
+    // Close file
+    fclose(fp);
+
+    // Finished
+    pc.printf("____________________________________________________________\r\n\r\n");
+    pc.printf("\n\rProgram exited normally. End of line.\n\r");
+
+}
+