andylvua/PCO_STM32LedCounter_Lab

Principles of Computer Organization. Lab 5. Led carousel and binary counter

Lab 5. STM32 Discovery Kit

Team members: Andrii Yaroshevych, Pavlo Kryven

Board: STM32F411E-DISCO

Prerequisites

Hardware

• Discovery Kit with STM32F411VE MCU

Software

• STM32CubeIDE version 1.11.0 is highly recommended

Note

You can use any other IDE, but you will need to configure it manually.

Compilation and Flashing

To compile the project in case of using other IDE, you will need to use the GNU Arm Embedded Toolchain. You can download it from here

If you are using STM32CubeIDE, you can use the following steps to compile and flash the project after opening it:

1. Select the project in the Project Explorer
2. Right-click on the project and select Build Project
3. Right-click on the project and select Run As -> 1 STM32 C/C++ Application

Installation

Clone the repository to your local machine using the following command:

$ mkdir ~/workspace
$ cd ~/workspace
$ git clone https://github.com/ucu-cs/stm32_5-1-kryven_yaroshevych

and open the project in STM32CubeIDE.

Usage

Connect the Discovery Kit to your PC using the USB cable and flash the project to the board as described in paragraph Compilation and Flashing

Task 1. Led carousel

After flashing the project, the LEDs on the board will start to blink in a carousel fashion. The direction of the carousel can be changed by pressing the User button on the board.

Note

You can adjust the speed of the carousel by changing the value of the PWM_DELAY constant in the main.c file.

Demonstration

Task 2. Led counter

To complete this task, you will need to assemble the circuit shown below:

For better quality, you can see the pdf version of the schematic.

After flashing the project, the LEDs on the external LED bar will represent the number of times an external button was pressed in binary format.

As additional functionality, if you hold the external button for 500ms counter will automatically increment by 1 every 100ms.

Note

This delays, respectively, can be adjusted by changing the values of the HOLD_DELAY and AUTO_COUNT_DELAY constants in the main.c file.

To reset the counter, you can press the RESET button on the board.

Demonstration

Basic functionality:

Auto count functionality demonstration:

Additional tasks

Led carousel

• Task 1: Use PWM to control LED brightness
• Task 2: Implement by relying on interrupts

Led counter

• Task 1: Implement by relying on interrupts

Configuration

The project was configured using the STM32CubeMX. The configuration files can be found in the project directories - led_carousel/led_carousel.ioc and led_counter/led_counter.ioc.

Steps to configure the project using STM32CubeMX:

Led carousel

1. Open STM32CubeMX
2. Open the .ioc configuration file
3. For internal LED pins (PD12 - PD15) select TIM4_CHx mode:
   • PD12 - TIM4_CH1
   • PD13 - TIM4_CH2
   • PD14 - TIM4_CH3
   • PD15 - TIM4_CH4

4. Go to the Pinout & Configuration tab and select TIM4 in the Timers section:

Set all the channels to PWM Generation mode and select Internal Clock as the clock source.

Also, set the Counter Period value to 1000-1:

These steps are required to configure the PWM for the internal LEDs.

5. On the Pinout & Configuration tab, add user labels to the LED pins and User button:
   • LED1 - PD12
   • LED2 - PD13
   • LED3 - PD14
   • LED4 - PD15
   • PUSH_BUTTON - PA0_WKUP

6. Go to the System Core tab and select NVIC section:

allow the EXTI line0 interrupt to make the User button work.

Go to the GPIO tab and select the PA0_WKUP pin:

set the GPIO mode mode to External Interrupt with Rising/Falling edge trigger detection

7. Go to the System Core tab and select RCC section:

Set both HSE and LSE to Crystal/Ceramic Resonator.

Finally, generate the code and open the project in STM32CubeIDE.

Led counter

1. In STM32CubeMX, open the .ioc configuration file
2. For external LED pins (PE6 - PE15) select GPIO_Output mode on the Pinout & Configuration tab:

3. For external button pin (PA1) select GPIO_EXTI1 mode:

also, give it a user label EXTERNAL_BUTTON.

4. Go to the System Core tab and select NVIC section:

allow the EXTI line1 interrupt to make the external button work.

Go to the GPIO tab and select the PA1 pin:

set the GPIO mode mode to External Interrupt with Rising/Falling edge trigger detection

5. Go to the System Core tab and select RCC section:

Set both HSE and LSE to Crystal/Ceramic Resonator.

Finally, generate the code and open the project in STM32CubeIDE.

License

The MIT License (MIT)

Copyright © 2022. Andrii Yaroshevych, Pavlo Kryven