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[stm32f429i-discovery] Added tick blink example.

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This commit is contained in:
Piotr Esden-Tempski
2015-01-14 18:28:00 -08:00
parent 25d924f699
commit 50b3522e7a
3 changed files with 130 additions and 0 deletions
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examples/stm32/f4/stm32f429i-discovery/tick_blink/Makefile Normal file
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##
## This file is part of the libopencm3 project.
##
## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
##
## 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/>.
##
BINARY = tick_blink
LDSCRIPT = ../stm32f429i-discovery.ld
include ../../Makefile.include

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examples/stm32/f4/stm32f429i-discovery/tick_blink/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This example is the same as fancy_blink except that it uses the
systick timer to generate time accurate delays. Shows how to set
up the systick timer to create an interrupt every millisecond and
how to write a delay routine (msleep) that can then delay for a
specific number of milliseconds.
Board connections:
------------------
<none required>

91
examples/stm32/f4/stm32f429i-discovery/tick_blink/tick_blink.c Normal file
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/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2011 Damjan Marion <damjan.marion@gmail.com>
* Copyright (C) 2011 Mark Panajotovic <marko@electrontube.org>
* Copyright (C) 2013 Chuck McManis <cmcmanis@mcmanis.com>
*
* 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/>.
*/
/* This version derived from fancy blink */
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/cm3/nvic.h>
#include <libopencm3/cm3/systick.h>
/* monotonically increasing number of milliseconds from reset
* overflows every 49 days if you're wondering
*/
volatile uint32_t system_millis;
/* Called when systick fires */
void sys_tick_handler(void)
{
system_millis++;
}
/* sleep for delay milliseconds */
static void msleep(uint32_t delay)
{
uint32_t wake = system_millis + delay;
while (wake > system_millis);
}
/* Set up a timer to create 1mS ticks. */
static void systick_setup(void)
{
/* clock rate / 1000 to get 1mS interrupt rate */
systick_set_reload(168000);
systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
systick_counter_enable();
/* this done last */
systick_interrupt_enable();
}
/* Set STM32 to 168 MHz. */
static void clock_setup(void)
{
rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_168MHZ]);
/* Enable GPIOG clock. */
rcc_periph_clock_enable(RCC_GPIOG);
}
static void gpio_setup(void)
{
/* Set GPIO13-14 (in GPIO port G) to 'output push-pull'. */
gpio_mode_setup(GPIOG, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE,
GPIO13 | GPIO14);
}
int main(void)
{
clock_setup();
gpio_setup();
systick_setup();
/* Set two LEDs for wigwag effect when toggling. */
gpio_set(GPIOG, GPIO13);
/* Blink the LEDs (PG13 and PG14) on the board. */
while (1) {
gpio_toggle(GPIOG, GPIO13 | GPIO14);
msleep(100);
}
return 0;
}