libopencm3/examples/stm32/f1/other/systick/systick.c

76 lines
2.0 KiB
C

/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2010 Thomas Otto <tommi@viadmin.org>
*
* 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/f1/rcc.h>
#include <libopencm3/stm32/f1/flash.h>
#include <libopencm3/stm32/f1/gpio.h>
#include <libopencm3/stm32/nvic.h>
#include <libopencm3/stm32/systick.h>
u32 temp32;
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 sys_tick_handler(void)
{
temp32++;
/* We call this handler every 1ms so 1000ms = 1s on/off. */
if (temp32 == 1000) {
gpio_toggle(GPIOB, GPIO6); /* LED2 on/off */
temp32 = 0;
}
}
int main(void)
{
rcc_clock_setup_in_hse_16mhz_out_72mhz();
gpio_setup();
gpio_clear(GPIOB, GPIO7); /* LED1 on */
gpio_set(GPIOB, GPIO6); /* LED2 off */
temp32 = 0;
/* 72MHz / 8 => 9000000 counts per second */
systick_set_clocksource(STK_CTRL_CLKSOURCE_AHB_DIV8);
/* 9000000/9000 = 1000 overflows per second - every 1ms one interrupt */
systick_set_reload(9000);
systick_interrupt_enable();
/* Start counting. */
systick_counter_enable();
while (1); /* Halt. */
return 0;
}