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Diffstat (limited to 'examples/stm32/f4/stm32f4-discovery/button/button.c')
-rw-r--r--examples/stm32/f4/stm32f4-discovery/button/button.c79
1 files changed, 79 insertions, 0 deletions
diff --git a/examples/stm32/f4/stm32f4-discovery/button/button.c b/examples/stm32/f4/stm32f4-discovery/button/button.c
new file mode 100644
index 0000000..e872887
--- /dev/null
+++ b/examples/stm32/f4/stm32f4-discovery/button/button.c
@@ -0,0 +1,79 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>,
+ * Copyright (C) 2010 Piotr Esden-Tempski <piotr@esden.net>
+ * Copyright (C) 2011 Stephen Caudle <scaudle@doceme.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/stm32/f4/rcc.h>
+#include <libopencm3/stm32/f4/gpio.h>
+
+u16 exti_line_state;
+
+/* Set STM32 to 168 MHz. */
+void clock_setup(void)
+{
+ rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_168MHZ]);
+}
+
+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);
+}
+
+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;
+
+ clock_setup();
+ button_setup();
+ gpio_setup();
+
+ /* Blink the LED (PD12) on the board. */
+ while (1) {
+ gpio_toggle(GPIOD, GPIO12);
+
+ /* Upon button press, blink more slowly. */
+ exti_line_state = GPIOA_IDR;
+ if ((exti_line_state & (1 << 0)) != 0) {
+ for (i = 0; i < 3000000; i++) /* Wait a bit. */
+ __asm__("nop");
+ }
+
+ for (i = 0; i < 3000000; i++) /* Wait a bit. */
+ __asm__("nop");
+ }
+
+ return 0;
+}