![]() So it will be defined inside the setup function. A pinMode function is used for the declaration of digital pins. In Arduino IDE, the setup function is used for declaration or initialization. If you want to add a delay of one second between turning on and turning off an LED, you will use delay(1000).ĭelay(2000) // waits for two second setup() This function is used to generate delays in milliseconds. digitalWrite(PD_2, HIGH) // sets the PD_2 pin as digital highĭigitalWrite(PD_2, LOW) // sets the PD_2 pin as digital low delay(value) ![]() For example, if you write digitalWrite(PD_2, HIGH), it will make pin number PD_2 logic HIGH or 3.3 volts and if you write digitalWrite(PD_2, LOW), it will make digital output pin PD_2 LOW or you will get zero volts at the output pin. A first argument is a pin number and the second value to this function is logic state either ‘HIGH’ or ‘LOW’. This function sets or clears digital output pins if the pin has been configured as a digital output pin with pinMode() function. PinMode(PA_5, INPUT) // configure PA_5 pin as a digital output pin digitalWrite(pin_number, value) PinMode(PA_7, OUTPUT) // configure PA_7 pin as a digital output pin pinMode(PD_2, OUTPUT) // configure PD_2 pin as a digital output pin For example, if we write pinMode(22, OUTPUT), it will declare pin number 22 as a digital output pin. The second argument is either INPUT or OUTPUT. The first argument to this function is a pin number or pin name to which you want to declare either as an input or output. This function is used to configure GIPO pins mode either as an input or output. If you have already used Arduino IDE for Arduino, ESP32, or ESP8266 programming, you will be already familiar with these functions : pinMode(pin_name, pin_mode) These routines are used to configure GPIO pins. To write LED blinking code for STM32 Nucleo, first, we need to understand three main functions available in Arduino IDE. Program STM32 Nucleo GPIO pins with Arduino IDE The following diagrams of different connectors of Nucleo-F103RB board show various GPIO pins for UART, I2C, SPI, ADC, CAN, Timers output, and USB communication. ![]() But you can use only one functionality at a time. We can use any one of these pins as a digital input or digital output.Įach GPIO pin may have multiple functions. Various features of Nucleo-F103RB are mentioned below: Features and PeripheralsĪccording to the above table, this STM32 Nucleo board has 51 general purpose input-output pins. The Nucleo-F103RB board comes with an STM32F103RBT6 microcontroller which is ARM®32-bit Cortex®-M3 CPU. But you can use any other Nucleo board also and follow the same instructions to use GPIO pins as digital output pins. But the one which we are going to use in this tutorial is a Nucleo-F103RB board. ‘Nucleo’ STM32F031K6 board with a button.As discussed in the previous tutorial, there are many variants of STM32 Nucleo boards are available. The green ‘LD3’ LED is attached to pin B3 on the board. The 100nF capacitor across the button should help reduce noise, one side of the button connects to ground through a jumper wire, and I put a 470Ω resistor between the other side of the button and pin B1. Strangely, the B1 pin is labeled ‘D6’ on the Nucleo boards I think that ST wanted to use the same footprint and labeling as the popular Arduino Nano. You can find the actual pin mappings in section 6.11 of this reference document, or they’re also printed on the informational card that comes with the board. The resistor and capacitor are both optional – they’re just a very simple form of debouncing. The STM32 chips have a lot of functionality which is not easy to represent in the standard C language. It has a number of hardware “Peripherals” to make it easier for you write programs which interact with the real world. They can do things like speak common communication protocols with other chips, run actions on timers, and send general-purpose signals to the pins connected to the chip. The way that we read and program these peripherals is to check and set certain values at specific memory addresses. For example, in this tutorial we will set a bit to 1 in an “Output Data Register” to pull a pin’s voltage high enough to turn on an LED, and reset the same bit to 0 to pull the pin to ground and turn the LED off. The companies which make these chips – ST Microelectronics in this case – usually also provide free header files which have definitions for which memory addresses go to which peripherals, and which bits do what.
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