But how to do that with PSoC 4
Configuring the PWM module
Formula
Calculating Frequency and Duty Cycle
Important : PWM Pin must be Checked as Hardware Connection
Servo in Action

Published March 8, 2016 © GPL3+

PSoC 4 : How to Control a Servo

This is a tutorial about controlling a Servo with PSoC by generating PWM, adjusting Frequency and Duty Cycle!

IntermediateProtip1 hour9,651

Things used in this project

Hardware components

Cypress PSoC 4 Prototyping Kit

Servos (Tower Pro MG996R)

Micro Servo SG90 Tower Pro

Story

Controlling a Servo with Arduino is damn easy ! There are libraries to do things, you don't need to know what's going on with the control signal that commands the servo. There is an Arduino tutorial for those who might need

Arduino Servo Tutorial

But how to do that with PSoC 4 ?

According to SG90 Micro Servo (Tower Pro) datasheet, you have to make PWM signal like this to control the Servo -

Servo control pulse

Configuring the PWM module

The answer is TCPWM component, but wait ! How do I make a 50 Hz signal (20 mS) and vary the Duty cycle between 5% (1mS) to 10 % (2mS) ?

Setting up PWM Component

By Changing the Value of Period from "1 to 65535", we can vary PWM Frequency.
By Changing the Value of Compare from "1 to Period Value", we can vary Duty Cycle.
By Changing the Value of fclk ( Clock signal to PWM component ), we can vary the Frequency range.
The larger the fclk, the higher is the max frequency .

Configuring Frequency and Duty

Formula

Formulas for this Configuration of PWM (Center Aligned i.e. symmetric PWM) -

Period = Fclk / (2 X Desired Frequency )

Compare = Period - ( Desired Duty X Period )

Calculating Frequency and Duty Cycle

Here, Fclk for the PWM Component is chosen 480 kHz,

We need a PWM signal of 50 Hz ( Our Desired Freq )

So, Period = 480000 / ( 2 X 50 ) = 4800

and Compare (min) = 4800 - ( 10% X 4800 ) = 4320

Compare (max) = 4800 - ( 5% X 4800 ) = 4560

Varying the Compare value between 4320 to 4560, we can control the servo because it will generate the desired signal required to do the job !

PWM0_WriteCompare(value) API ( or Function) is used to change the Duty Cycle from C code, which controls the position of the servo !

Visualizing Output Waveform

Important : PWM Pin must be Checked as Hardware Connection !

Pin Driven by Internal H/W

Otherwise , there will be no output !

Servo in Action

Sorry for the crappy quality video. Don't have a better camera right now!

Servo Motion

Code

/* ========================================
 *
 * Copyright YOUR COMPANY, THE YEAR
 * All Rights Reserved
 * UNPUBLISHED, LICENSED SOFTWARE.
 *
 * CONFIDENTIAL AND PROPRIETARY INFORMATION
 * WHICH IS THE PROPERTY OF your company.
 *
 * ========================================
*/
#include <project.h>
//long freq=50;
int x=4520;
int main()
{
    /* Place your initialization/startup code here (e.g. MyInst_Start()) */

    PWM0_Start();
  
     CyGlobalIntEnable;  /* Uncomment this line to enable global interrupts. */
    for(;;)
    {
    
    while(1)
    {
     
    
  
    while(1)
    {
        
       PWM0_WriteCompare(x); 
        x+=24;
        CyDelay(1500);
        if (x>=4540){x=4320;}
    }

    
    }
    
    }
      
   
}

Credits

Shahariar

74 projects • 266 followers

"What Kills a 'Great life' is a 'Good Life', which is Living a Life Inside While Loop"

PSoC 4 : How to Control a Servo

Things used in this project

Hardware components

Story

But how to do that with PSoC 4 ?

Configuring the PWM module

Formula

Calculating Frequency and Duty Cycle

Important : PWM Pin must be Checked as Hardware Connection !

Servo in Action

Schematics

Servo connections to PSoC

Code

Main C

PSoC Codes and Design Files

Credits

Shahariar

Comments

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PSoC 4 : How to Control a Servo

PSoC 4 : How to Control a Servo

Things used in this project

Hardware components

Story

But how to do that with PSoC 4 ?

Configuring the PWM module

Formula

Calculating Frequency and Duty Cycle

Important : PWM Pin must be Checked as Hardware Connection !

Servo in Action

Schematics

Servo connections to PSoC

Code

Main C

PSoC Codes and Design Files

Credits

Shahariar

Comments

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