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[stm32f429i-discovery] Added random blinking example.

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This commit is contained in:
Piotr Esden-Tempski
2015-01-14 18:44:04 -08:00
parent 1346cd0156
commit ddd0312b10
3 changed files with 133 additions and 0 deletions
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25
examples/stm32/f4/stm32f429i-discovery/random/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 = random
LDSCRIPT = ../stm32f429i-discovery.ld
include ../../Makefile.include

12
examples/stm32/f4/stm32f429i-discovery/random/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This example randomly blinks the GREEN LED on the ST STM32F429IDISCOVERY eval
board.
Board connections:
------------------
<none required>

96
examples/stm32/f4/stm32f429i-discovery/random/random.c Normal file
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/*
* This file is part of the libopencm3 project.
*
* 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/cm3/common.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/f4/rng.h>
static void rcc_setup(void)
{
rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_120MHZ]);
/* Enable GPIOG clock for onboard leds. */
rcc_periph_clock_enable(RCC_GPIOG);
/* Enable rng clock */
rcc_periph_clock_enable(RCC_RNG);
}
static void rng_setup(void)
{
/* Enable interupt */
/* Set the IE bit in the RNG_CR register. */
RNG_CR |= RNG_CR_IE;
/* Enable the random number generation by setting the RNGEN bit in
the RNG_CR register. This activates the analog part, the RNG_LFSR
and the error detector.
*/
RNG_CR |= RNG_CR_RNGEN;
}
static void gpio_setup(void)
{
/* Setup onboard led */
gpio_mode_setup(GPIOG, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE,
GPIO13 | GPIO14);
}
/* Tried to folow the guidelines in the stm32f4 user manual.*/
static uint32_t random_int(void)
{
static uint32_t last_value;
static uint32_t new_value;
uint32_t error_bits = 0;
error_bits = RNG_SR_SEIS | RNG_SR_CEIS;
while (new_value == last_value) {
/* Check for error flags and if data is ready. */
if (((RNG_SR & error_bits) == 0) &&
((RNG_SR & RNG_SR_DRDY) == 1)) {
new_value = RNG_DR;
}
}
last_value = new_value;
return new_value;
}
int main(void)
{
int i, j;
rcc_setup();
gpio_setup();
rng_setup();
while (1) {
uint32_t rnd;
rnd = random_int();
for (i = 0; i != 32; i++) {
if ((rnd & (1 << i)) != 0) {
gpio_set(GPIOG, GPIO13);
} else {
gpio_clear(GPIOG, GPIO13);
}
/* Delay */
for (j = 0; j != 5000000; j++) {
__asm__("nop");
}
}
}
}