Diff: main.cpp

Revision:

1:56cc90ae5080

Parent:

0:ee9aab897b59

--- a/main.cpp	Mon Apr 20 15:07:18 2015 +0000
+++ b/main.cpp	Tue May 12 09:46:06 2015 +0000
@@ -3,7 +3,8 @@
 * @author  Petr Douša
 * @version V1.0
 * @date    20-April-2015
-* @brief   This program use digital output and regular PWM output to modulate PWM
+* @brief   This program uses digital output (software) and hardware PWM output
+*          to generate two separate PWMs
 ***********************************************************************************/
 
 /**********************************************************************************/
@@ -57,7 +58,7 @@
 int off_delay = 0;
 
 //mbed - initialization of peripherals
-Timeout timer;              // timer use with digital IO 
+Timeout timer;              // timer used with digital IO 
 DigitalOut my_pwm(LED1);    // digital IO used by pwm_io function
 PwmOut      real_pwm(PA_8); // regular PWM output
 
@@ -65,7 +66,7 @@
 
 /*******************************************************************************
 * Function Name  : toggleOn.
-* Description    : Set high on digital pin and set and start timer.
+* Description    : Set high level on digital pin and timer startup.
 * Input          : None.
 * Output         : None.
 * Return         : None.
@@ -78,7 +79,7 @@
 
 /*******************************************************************************
 * Function Name  : toggleOff.
-* Description    : Set low on digital pin and set and start timer.
+* Description    : Set low level on digital pin and set and start timer.
 * Input          : None.
 * Output         : None.
 * Return         : None.
@@ -91,23 +92,23 @@
 
 /*******************************************************************************
 * Function Name  : pwm_io.
-* Description    : Set variables and start PWM on digital output.
-* Input          : p_us: signal period in micro_seconds ,dc: signal duty-cycle (0.0 to 1.0) .
-* Output         : on_delay: time to be digital output on high ,off_delay: time to be digital output on low: .
+* Description    : Set variables and start software PWM on digital output.
+* Input          : p_us: signal period in micro_seconds, dc: signal duty-cycle (0.0 to 1.0) .
+* Output         : on_delay: output ON time, off_delay: output OFF time
 * Return         : None.
 *******************************************************************************/
 void pwm_io(int p_us, float dc)
 {
     timer.detach();                 // shutdown timer
     if ((p_us == 0) || (dc == 0)) { // if duty-cycle is 0
-        my_pwm = 0;                 // set low regular IO to low
+        my_pwm = 0;                 // set high IO to low
         return;
     }
     if (dc >= 1) {                  // if duty-cycle is 1 and more
-        my_pwm = 1;                 // set high regular IO to low
+        my_pwm = 1;                 // set high IO to low
         return;
     }
-    on_delay = (int)(p_us * dc);    // calculate time to be digital output on high and low
+    on_delay = (int)(p_us * dc);    // calculate the time
     off_delay = p_us - on_delay;
     toggleOn();                     // call function toggleOn to start PWM
 }
@@ -123,24 +124,24 @@
 {
     double a=0;                 // variable to set duty-cycle
 
-    real_pwm.period_us(2000);   // set period of real PWM to 2 milliseconds
-    real_pwm.write(a);          // set duty-cycle as it is in variable a (0 at this point)
+    real_pwm.period_us(2000);   // set period of hardware PWM to 2 milliseconds
+    real_pwm.write(a);          // set duty-cycle from a (0 at this point)
 
 
-    pwm_io(2000, a);            // set period of digital IO PWM to 2 ms and duty-cycle as in variable a (0 at this point)
+    pwm_io(2000, a);            // set period of software PWM to 2 ms and duty-cycle as in variable a (0 at this point)
 
 
-    while(1) {                  // main cykl of program
+    while(1) {                  // main cycle of the program
 
-        if(a>=1) {              // if variable is grater then 1 set it 0 else attributable 0.01
+        if(a>=1) {              // if variable is grater then 1 set it 0 else increment 0.01
             a=0;
         } else {
             a=a+0.01;
         }
 
-        real_pwm.write(a);      // set duty-cycle of real PWM as as it is in variable a
+        real_pwm.write(a);      // set duty-cycle of hardware PWM as as it is in variable a
 
-        pwm_io(2000, a);        // set duty-cycle of digital IO PWM as as it is in variable a and period to 2 ms
+        pwm_io(2000, a);        // set duty-cycle of software PWM as as it is in variable a and period to 2 ms
 
         wait(0.05);             // wait some time in milliseconds
     }