aboutsummaryrefslogtreecommitdiff
path: root/examples/stm32/f1/other/timer_interrupt/timer.c
diff options
context:
space:
mode:
Diffstat (limited to 'examples/stm32/f1/other/timer_interrupt/timer.c')
-rw-r--r--examples/stm32/f1/other/timer_interrupt/timer.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/examples/stm32/f1/other/timer_interrupt/timer.c b/examples/stm32/f1/other/timer_interrupt/timer.c
new file mode 100644
index 0000000..422df88
--- /dev/null
+++ b/examples/stm32/f1/other/timer_interrupt/timer.c
@@ -0,0 +1,85 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2010 Thomas Otto <tommi@viadmin.org>
+ *
+ * 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/f1/rcc.h>
+#include <libopencm3/stm32/f1/flash.h>
+#include <libopencm3/stm32/f1/gpio.h>
+#include <libopencm3/stm32/timer.h>
+#include <libopencm3/stm32/nvic.h>
+
+void gpio_setup(void)
+{
+ /* Enable GPIOB clock. */
+ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPBEN);
+
+ /* Set GPIO6/7 (in GPIO port B) to 'output push-pull' for the LEDs. */
+ gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ,
+ GPIO_CNF_OUTPUT_PUSHPULL, GPIO6);
+ gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ,
+ GPIO_CNF_OUTPUT_PUSHPULL, GPIO7);
+}
+
+void nvic_setup()
+{
+ /* without this the timer interrupt routine will never be called */
+ nvic_enable_irq(NVIC_TIM2_IRQ);
+ nvic_set_priority(NVIC_TIM2_IRQ, 1);
+}
+
+void tim2_isr()
+{
+ /* LED2 on/off */
+ gpio_toggle(GPIOB, GPIO6);
+
+ /* clear interrrupt flag */
+ TIM_SR(TIM2) &= ~TIM_SR_UIF;
+}
+
+int main(void)
+{
+ rcc_clock_setup_in_hse_16mhz_out_72mhz();
+ gpio_setup();
+ nvic_setup();
+
+ gpio_clear(GPIOB, GPIO7); /* LED1 on */
+ gpio_set(GPIOB, GPIO6); /* LED2 off */
+
+ rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_TIM2EN);
+
+ /* the goal is to let the LED2 glow for a second and then be off for a second */
+
+ /* Set timer start value */
+ TIM_CNT(TIM2) = 1;
+
+ /* Set timer prescaler. 72MHz/1440 => 50000 counts per second */
+ TIM_PSC(TIM2) = 1440;
+
+ /* End timer value. If this value is reached an interrupt is generated */
+ TIM_ARR(TIM2) = 50000;
+
+ /* Update interrupt enable */
+ TIM_DIER(TIM2) |= TIM_DIER_UIE;
+
+ /* Start timer */
+ TIM_CR1(TIM2) |= TIM_CR1_CEN;
+
+ while(1); /* Halt. */
+
+ return 0;
+}