Added a simple exti test using rising and falling trigger instead of sampling the gpio pin to determine the current state of the pin.

examples/stm32/stm32-h103/exti_rising_falling/Makefile

@@ -0,0 +1,23 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## 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/>.
+##
+
+BINARY = exti_rising_falling
+
+include ../../Makefile.include
+

examples/stm32/stm32-h103/exti_rising_falling/exti_rising_falling.c

@@ -0,0 +1,99 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>,
+ *               2010 Piotr Esden-Tempski <piotr@esden.net>
+ *
+ * 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/nvic.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/exti.h>
+
+#define FALLING 0
+#define RISING 1
+
+u16 exti_direction = FALLING;
+
+/* Set STM32 to 72 MHz. */
+void clock_setup(void)
+{
+	rcc_clock_setup_in_hse_8mhz_out_72mhz();
+
+}
+
+void gpio_setup(void)
+{
+	/* Enable GPIOC clock. */
+	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
+
+	/* Set GPIO12 (in GPIO port C) to 'output push-pull'. */
+	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ,
+		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
+}
+
+void exti_setup(void)
+{
+	/* Enable GPIOA clock. */
+	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN);
+
+	/* Enable AFIO clock. */
+	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_AFIOEN);
+
+	/* Enable EXTI0 interrupt */
+	nvic_enable_irq(NVIC_EXTI0_IRQ);
+
+	/* Set GPIO0 (in GPIO port A) to 'input open-drain'. */
+	gpio_set_mode(GPIOA, GPIO_MODE_INPUT,
+		      GPIO_CNF_INPUT_PULL_UPDOWN, GPIO0);
+	gpio_set(GPIOA, GPIO0);
+
+	/* configure EXTI subsystem */
+	exti_select_source(EXTI0, GPIOA);
+	exti_direction = FALLING;
+	exti_set_trigger(EXTI0, EXTI_TRIGGER_FALLING);
+	exti_enable_request(EXTI0);
+}
+
+void exti0_isr()
+{
+	exti_reset_request(EXTI0);
+
+	if (exti_direction == FALLING) {
+		gpio_set(GPIOC, GPIO12);
+		exti_direction = RISING;
+		exti_set_trigger(EXTI0, EXTI_TRIGGER_RISING);
+	} else {
+		gpio_clear(GPIOC, GPIO12);
+		exti_direction = FALLING;
+		exti_set_trigger(EXTI0, EXTI_TRIGGER_FALLING);
+	}
+}
+
+int main(void)
+{
+
+	clock_setup();
+	gpio_setup();
+	exti_setup();
+
+	/* Blink the LED (PC12) on the board. */
+	while (1) {
+		__asm("nop");
+	}
+
+	return 0;
+}

examples/stm32/stm32-h103/exti_rising_falling/exti_rising_falling.ld

@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * 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/>.
+ */
+
+/* Linker script for Olimex STM32-H103 (STM32F103RBT6, 128K flash, 20K RAM). */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 128K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32.ld
+