How to detect a button click on stm32f4open?

Question

I like to detect a button press to switch through 4 LEDs on the board, for example

Click-1 --> LED 1 on Click-2 --> LED 2 on Click-3 --> LED 3 on Click-4 --> LED 4 on Click-5 --> LED 1 off Click-6 --> LED 2 off Click-7 --> LED 3 off Click-8 --> LED 4 off Click-9 --> LED 1 on … 

as much as possible, but button click detection does not work as expected:

 /* * This file is part of the libopencm3 project. * * Copyright (C) 2009 Uwe Hermann < [e-mail] >, * Copyright (C) 2010 Piotr Esden-Tempski < [e-mail] > * Copyright (C) 2011 Stephen Caudle < [e-mail] > * * This library is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library. If not, see <http://www.gnu.org/licenses/>. */ #include <libopencm3/stm32/f4/rcc.h> #include <libopencm3/stm32/f4/gpio.h> uint16_t exti_line_state; /* Set STM32 to 168 MHz. */ static void clock_setup(void) { rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_168MHZ]); } static void gpio_setup(void) { /* Enable GPIOD clock. */ rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPDEN); /* Set GPIO12 (in GPIO port D) to 'output push-pull'. */ gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO12 | GPIO13 | GPIO14 | GPIO15); } static void button_setup(void) { /* Enable GPIOA clock. */ rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPAEN); /* Set GPIO0 (in GPIO port A) to 'input open-drain'. */ gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO0); } int main(void) { int i; i = 1; clock_setup(); button_setup(); gpio_setup(); while (1) { exti_line_state = GPIOA_IDR; if ((exti_line_state & (1 << 0)) != 0) { if(i == 1){ i = 2; gpio_toggle(GPIOD, GPIO12); } if(i == 2){ i = 3; gpio_toggle(GPIOD, GPIO13); } if(i == 3){ i = 4; gpio_toggle(GPIOD, GPIO14); } if(i == 4){ i = 5; gpio_toggle(GPIOD, GPIO15); } if(i == 5){ i = 1; //Shut off all LEDs } } } return 0; } 

Answer 1

OK, the answer is very simple:

 #include <libopencm3/stm32/f4/rcc.h> #include <libopencm3/stm32/f4/gpio.h> #include <libopencm3/stm32/f4/adc.h> #include <stddef.h> #include <stdlib.h> int count = 1; /* Set STM32 to 168 MHz. */ static void clock_setup(void) { rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_168MHZ]); } static void gpio_setup(void) { /* Enable GPIOD clock. */ rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPDEN); /* Set GPIO12 (in GPIO port D) to 'output push-pull'. */ gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO12 | GPIO13 | GPIO14 | GPIO15); } static void button_setup(void) { /* Enable GPIOA clock. */ rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPAEN); /* Set GPIO0 (in GPIO port A) to 'input open-drain'. */ gpio_mode_setup(GPIOA, GPIO_MODE_INPUT, GPIO_PUPD_NONE, GPIO0); } static void changeLEDs(void) { if(count == 1){ count = 2; gpio_set(GPIOD, GPIO12); return; } if(count == 2){ count = 3; gpio_set(GPIOD, GPIO13); return; } if(count == 3){ count = 4; gpio_set(GPIOD, GPIO14); return; } if(count == 4){ count = 5; gpio_set(GPIOD, GPIO15); return; } if(count == 5){ count = 6; gpio_clear(GPIOD, GPIO12); return; } if(count == 6){ count = 7; gpio_clear(GPIOD, GPIO13); return; } if(count == 7){ count = 8; gpio_clear(GPIOD, GPIO14); return; } if(count == 8){ count = 1; gpio_clear(GPIOD, GPIO15); return; } } int main(void) { gpio_setup(); clock_setup(); button_setup(); int i; while (1) { if(GPIOA_IDR & 0x0001){ for (i = 0; i < 6000000; i++) /* Wait a bit. */ __asm__("nop"); changeLEDs(); } } return 0; }