# Tutorial: arduino-stm32 Part1 ## Preparation MCU board: Nucleo-F401RE [HUINS experiment kit](https://ykkim.gitbook.io/ec/hardware/experiment-hardware/huins-embedded-kit#pin-map) ## **GPIO Digital In/Out** We are going to create a simple program that turns LED(LD2) on and off by pressing the user button(BT1). ### [pinMode()](https://www.arduino.cc/reference/en/language/functions/digital-io/pinmode/) Configures the specified pin to behave either as an input or an output. ```cpp pinMode(pin, mode) ``` * pin: the pin number to set the model of. * mode: INPUT, OUTPUT or INPUT\_PULLUP. > Look up for pinMode() function in arduino reference for detail description. ### Example Create a new program named as ‘**TU\_arduino\_GPIO\_LED\_button**’. Write the following source code: [source code](https://github.com/ykkimhgu/EC-student/tree/main/stm32duino-tutorial). ```cpp const int btnPin = 3; const int ledPin = 13; int btnState = HIGH; void setup() { pinMode(ledPin, OUTPUT); pinMode(btnPin, INPUT); } void loop() { btnState = digitalRead(btnPin); if (btnState == HIGH) digitalWrite(ledPin, LOW); else digitalWrite(ledPin, HIGH); } ``` The user button pin is `PC13`, but this pin cannot be used in arduino. So, you should connect `PC13` to `pinName` `D3` by using wire. ![button pin connection](https://user-images.githubusercontent.com/91526930/186584565-3dc47e19-e5c5-43a2-b4c4-d4de8916a2c8.png) Click on **upload** button. Push the reset button(black) and check the performance. The LED(LD2) should be turned on when the button is pressed. ## **External Interrupt** We are going to create a simple program that turns LED(LD2) on triggered by **External Interrupt** of user button(BT1). ### [attachInterrupt()](https://www.arduino.cc/reference/en/language/functions/external-interrupts/attachinterrupt/) ```cpp attachInterrupt(digitalPinToInterrupt(pin), ISR, mode) ``` * digitalPinToInterrupt(pin): translate the digital pin to the specific interrupt number. * ISR: a function called whenever the interrupt occurs. * mode: defines when the interrupt should be trggered. (LOW, CHANGE, RISING, FALLING) ### Example Create new program as ‘**TU\_arduino\_ExtIn**’. Write the following code. ```cpp const int btnPin = 3; const int ledPin = 13; int btnState = HIGH; void setup() { pinMode(ledPin, OUTPUT); pinMode(btnPin, INPUT_PULLUP); attachInterrupt(digitalPinToInterrupt(btnPin), blink, CHANGE); } void loop() { } void blink(){ btnState = digitalRead(btnPin); if (btnState == HIGH) digitalWrite(ledPin, LOW); else digitalWrite(ledPin, HIGH); } ``` Click on **upload** button. Whenever the user button(BT1) is pressed (at fall), then the LED should be ON. When the button is released then the LED should be off. ### Exercise **Motion Detection Exercise** * Use External interrupt to get the digital in data from the motion sensor * When the userbutton is pressed, it should turn-off the LED. The experiment kit has IR motion sensor(HD-SEN0018) that detects a motion of an object nearby. It is often used in automatic lighting system at the front door. It is connected to `PinName` `D5` as DigitalIn. ![image](https://user-images.githubusercontent.com/91526930/186357289-990c7152-b4cb-4fd5-bd83-62b4a841d9c4.png) * [Hint:](https://github.com/ykkimhgu/EC-student/tree/main/tutorial/stm32duino-tutorial/exercise) ```cpp // set pin numbers const int motionPin = 5; // the number of the Motion detection sensor const int btnPin = 3; // the number of the push button pin const int ledPin = 13; // the number of the LED pin void setup() { // initialize the LED pin as an output: // your code // initialize the Motion detection sensor pin as an interrupt input: // your code // initialize the push button pin as an interrupt input: // your code } void loop() { } void motionDetected(){ // LED on // your code } void btnPressed(){ // LED off // your code } ``` ## Ticker (SysTick interrupt) We are going to create a simple program that uses System Timer Tick Interrupt that occurs periodically. Lets turn LED on and off at 1 sec of period. ### Add STM32Timer Interrupt Library Download the library as lastest version. > [STM32Timer Interrupt Library](https://www.arduino.cc/reference/en/libraries/stm32_timerinterrupt/) Add the library as .zip file. > On the menu bar, select **sketch > Include Library > Add .ZIP Library**. Then, open 'STM32\_TimerInterrupt-(version).zip'. ### STM32Timer class * STM32Timer ```cpp STM32Timer ITimer(TIMx); ITimer.attachInterruptInterval(period_us, TimerHandler) ``` * TIMx : Timer number (TIM1, TIM2, ...) * period\_us : Period of Timer (unit: microseconds) * TimerHandler : a function handling the timers run * STM32\_ISR\_Timer ```cpp STM32_ISR_Timer ISR_Timer; ISR_Timer.setInterval(period_ms, timerInterrupt); ``` * period\_ms : Period of ISR Timer (unit: miliseconds) * timerInterrupt : a function excuted whenever the period of ISR Timer. Use the STM32TimerInterrupt interface to set up a recurring interrupt; it calls a function repeatedly and at a specified rate. ### Example Create a new program named as ‘**TU\_arduino\_TimerInterrupt**’. You can make LED blink every second, even though there is no infinite loop. This is also called as the ‘Timer interrupt’ or ‘SysTick interrupt’. ```cpp #include "STM32TimerInterrupt.h" #define HW_TIMER_INTERVAL_MS 1000 STM32Timer ITimer(TIM1); // Init STM32 timer TIM1 const int ledPin = 13; void setup() { pinMode(ledPin, OUTPUT); ITimer.attachInterruptInterval(HW_TIMER_INTERVAL_MS * 1000, timerInterrupt); } void loop(){ } void timerInterrupt(){ digitalWrite(ledPin, !digitalRead(ledPin)); } ``` Click on **Upload** button. LED(LD2) should blink every second. ### Exercise **Buzz output exercise** * Buzz the sound for about 1 second that repeats for every 3 seconds. * e.g: 1 sec of buzzing then 2 secs of silence and repeat This experiment kit has a digital buzzer (MCKPI-G1410). It is connected at DigitalOut `PA13`. (But, you should wire `PA13` to `pinName` `D8`.) A simple example of using a buzzer: ```cpp void loop(){ if (buzzState == HIGH) tone(buzzPin, 100); else if (buzzState == LOW) noTone(buzzPin); } ``` ![buzzer pin connection](https://user-images.githubusercontent.com/91526930/186584724-e7159e35-670e-4225-8580-a07b23eb2d79.png) [Hint:](https://github.com/ykkimhgu/EC-student/tree/main/tutorial/stm32duino-tutorial/exercise) ```cpp #include "STM32TimerInterrupt.h" #define HW_TIMER_INTERVAL_MS 1000 STM32Timer ITimer(TIM1); // Init STM32 timer TIM1 // constants won't change. They're used here to set pin numbers: const int ledPin = 13; // the number of the LED pin const int buzzPin = 8; // the number of the buzzer pin // variables will change: int buzzState = LOW; int cnt = 0; void setup() { // initialize the LED pin as an output: // your code // Interval in microsecs // your code // Timer interrupt every 1sec // your code } void loop(){ if (buzzState == HIGH) tone(buzzPin, 100); else if (buzzState == LOW) noTone(buzzPin); } // Whenever ISR Timer interrupts, this function is excuted. void timerInterrupt(){ // Use 'cnt' and 'buzzState' variables // your code } ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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