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[stm32f429i-discovery] Added mandelbrot set example.

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Piotr Esden-Tempski
2015-01-14 18:51:45 -08:00
parent ddd0312b10
commit dfac3be665
3 changed files with 164 additions and 0 deletions
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examples/stm32/f4/stm32f429i-discovery/mandelbrot/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 = mandel
LDSCRIPT = ../stm32f429i-discovery.ld
include ../../Makefile.include

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examples/stm32/f4/stm32f429i-discovery/mandelbrot/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This example program demonstrates the floating point coprocessor usage on
the ST STM32F429IDISCOVERY eval board.
A mandelbrot fractal is calculated and sent as "ascii-art" image through
the USART1.
Board connections:
------------------
PA9 (USART1_TX) TTL serial output (38400,8,N,1)

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examples/stm32/f4/stm32f429i-discovery/mandelbrot/mandel.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 Stephen Caudle <scaudle@doceme.com>
* Copyright (C) 2012 Daniel Serpell <daniel.serpell@gmail.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/>.
*/
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/usart.h>
static void clock_setup(void)
{
/* Enable high-speed clock at 120MHz */
rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_120MHZ]);
/* Enable GPIOG clock for LED & USARTs. */
rcc_periph_clock_enable(RCC_GPIOG);
rcc_periph_clock_enable(RCC_GPIOA);
/* Enable clocks for USART1. */
rcc_periph_clock_enable(RCC_USART1);
}
static void usart_setup(void)
{
/* Setup USART1 parameters. */
usart_set_baudrate(USART1, 38400);
usart_set_databits(USART1, 8);
usart_set_stopbits(USART1, USART_STOPBITS_1);
usart_set_mode(USART1, USART_MODE_TX);
usart_set_parity(USART1, USART_PARITY_NONE);
usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
/* Finally enable the USART. */
usart_enable(USART1);
}
static void gpio_setup(void)
{
/* Setup GPIO pin GPIO13 on GPIO port G for LED. */
gpio_mode_setup(GPIOG, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO13);
/* Setup GPIO pins for USART1 transmit. */
gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9);
/* Setup USART1 TX pin as alternate function. */
gpio_set_af(GPIOA, GPIO_AF7, GPIO9);
}
/* Maximum number of iterations for the escape-time calculation */
#define maxIter 32
/* This array converts the iteration count to a character representation. */
static char color[maxIter+1] = " .:++xxXXX%%%%%%################";
/* Main mandelbrot calculation */
static int iterate(float px, float py)
{
int it = 0;
float x = 0, y = 0;
while (it < maxIter) {
float nx = x*x;
float ny = y*y;
if ((nx + ny) > 4) {
return it;
}
/* Zn+1 = Zn^2 + P */
y = 2*x*y + py;
x = nx - ny + px;
it++;
}
return 0;
}
static void mandel(float cX, float cY, float scale)
{
int x, y;
for (x = -60; x < 60; x++) {
for (y = -50; y < 50; y++) {
int i = iterate(cX + x*scale, cY + y*scale);
usart_send_blocking(USART1, color[i]);
}
usart_send_blocking(USART1, '\r');
usart_send_blocking(USART1, '\n');
}
}
int main(void)
{
float scale = 0.25f, centerX = -0.5f, centerY = 0.0f;
clock_setup();
gpio_setup();
usart_setup();
while (1) {
/* Blink the LED (PG13) on the board with each fractal drawn. */
gpio_toggle(GPIOG, GPIO13); /* LED on/off */
mandel(centerX, centerY, scale); /* draw mandelbrot */
/* Change scale and center */
centerX += 0.175f * scale;
centerY += 0.522f * scale;
scale *= 0.875f;
usart_send_blocking(USART1, '\r');
usart_send_blocking(USART1, '\n');
}
return 0;
}