Page 244 - ARM Based Microcontroller Projects Using MBED

230 8. INTERMEDIATE LEVEL PROJECTS

/*************************************************************************

GENERATE TRIANGULAR WAVEFORM
============================
This program generates a triangular waveform with 100 steps rising and 100
steps falling, where each step width is 100 microseconds. i.e. the period
of the waveform is 20ms
Author: Dogan Ibrahim
Date : August 2018
File : Triangular
**************************************************************************/
#include "mbed.h"
Serial MyPC(USBTX, USBRX);
AnalogOut aout(PA_4);

int main()
{
float k;

while(1) // Do forever
{
for(k = 0.0f; k < 1.0f; k = k + 0.01f) // Do 100 times
{
aout = k; // Analog out
wait_us(100.0); // Wait 100us
}

for(k = 1.0f; k > 0; k = k - 0.01f) // Do 100 times
{
aout = k; // Analog out
wait_us(100.0); // Wait 100us
}
}
}
FIG. 8.102 Program listing.

8.31.2 Aim
The aim of this project is to show how a sine waveform can be generated.

8.31.3 Circuit Diagram
In this project, analog input PA_4 is used as in the previous project.

8.31.4 The PDL
Fig. 8.105 shows the PDL of the program.