COMP2 PWM signal control example

  ******************** (C) COPYRIGHT 2014 STMicroelectronics *******************
  * @file    COMP/COMP_PWMSignalControl/readme.txt 
  * @author  MCD Application Team
  * @version V1.4.0
  * @date    24-July-2014
  * @brief   Description of the COMP2 PWM signal control example.
  ******************************************************************************
  *
  * Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
  * You may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *        http://www.st.com/software_license_agreement_liberty_v2
  *
  * Unless required by applicable law or agreed to in writing, software 
  * distributed under the License is distributed on an "AS IS" BASIS, 
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
  ******************************************************************************
   

Example Description

This example shows how to configure COMP2 peripheral to hold on safe state (low level) TIM1 channels as soon as COMP2 output is set at high level.

• COMP2 is configured as following:
  • Inverting input is internally connected to VREFINT = 1.22V
  • Non Inverting input is connected to PA3
  • Output is internally connected to TIM2 BKIN (Break Input)

• TIM1CLK is set to 48 MHz, the TIM1 Prescaler is equal to 0 so the TIM1 counter clock used is 48 MHz. TIM1 frequency is defined as follow: TIM1 channels frequency = TIM1 counter clock / (Period + 1) = 48000000 /(100 + 1) = 475 KHz.

• External voltage should be connected to PA3 (RV3 potentiometer can be used).

• Connect an oscilloscope to TIM1 channel PA8 to display waveform.

• While PA3 is lower than VREFINT (1.22V), PWM signal is displayed on PA8. While PA3 is higher than VREFINT, PA8 is in low level.

Directory contents

• COMP/COMP_PWMSignalControl/stm32f0xx_conf.h Library Configuration file
• COMP/COMP_PWMSignalControl/stm32f0xx_it.c Interrupt handlers
• COMP/COMP_PWMSignalControl/stm32f0xx_it.h Interrupt handlers header file
• COMP/COMP_PWMSignalControl/main.c Main program
• COMP/COMP_PWMSignalControl/main.h Main program header file
• COMP/COMP_PWMSignalControl/system_stm32f0xx.c STM32F0xx system source file

Note:

The "system_stm32f0xx.c" is generated by an automatic clock configuration tool and can be easily customized to meet user application requirements. To select different clock setup, use the "STM32F0xx_Clock_Configuration_VX.Y.Z.xls" provided with the AN4055 package available on ST Microcontrollers

Hardware and Software environment

• This example runs on STM32F0xx Devices.

• This example has been tested with STMicroelectronics STM320518-EVAL and STM32072B-EVAL including respectively STM32F051R8T6 and STM32F072VBT6 devices and can be easily tailored to any other supported device and development board.

• STM320518-EVAL Set-up
  • RV3 Potentiometer connected to PC.01 pin.
  • Connect PA.03 to PC.01 pin using a wire.
  • Connect an oscilloscope to PA.08 pin to display waveform.
• STM32072B-EVAL Set-up
  • RV3 Potentiometer connected to PC.00 pin.
  • Connect PA.03 to PC.00 pin using a wire.
  • Connect an oscilloscope to PA.08 pin to display waveform.

How to use it ?

In order to make the program work, you must do the following :

• Copy all source files from this example folder to the template folder under Project
• Open your preferred toolchain
• Select the appropriate workspace
• Rebuild all files and load your image into target memory
• Run the example

© COPYRIGHT STMicroelectronics