From dfac3be6654174c85ba4a1690edfe8ed6bddcb6a Mon Sep 17 00:00:00 2001 From: Piotr Esden-Tempski Date: Wed, 14 Jan 2015 18:51:45 -0800 Subject: [PATCH] [stm32f429i-discovery] Added mandelbrot set example. --- .../stm32f429i-discovery/mandelbrot/Makefile | 25 ++++ .../f4/stm32f429i-discovery/mandelbrot/README | 14 ++ .../stm32f429i-discovery/mandelbrot/mandel.c | 125 ++++++++++++++++++ 3 files changed, 164 insertions(+) create mode 100644 examples/stm32/f4/stm32f429i-discovery/mandelbrot/Makefile create mode 100644 examples/stm32/f4/stm32f429i-discovery/mandelbrot/README create mode 100644 examples/stm32/f4/stm32f429i-discovery/mandelbrot/mandel.c diff --git a/examples/stm32/f4/stm32f429i-discovery/mandelbrot/Makefile b/examples/stm32/f4/stm32f429i-discovery/mandelbrot/Makefile new file mode 100644 index 0000000..a3d17d9 --- /dev/null +++ b/examples/stm32/f4/stm32f429i-discovery/mandelbrot/Makefile @@ -0,0 +1,25 @@ +## +## This file is part of the libopencm3 project. +## +## Copyright (C) 2009 Uwe Hermann +## +## 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 . +## + +BINARY = mandel + +LDSCRIPT = ../stm32f429i-discovery.ld + +include ../../Makefile.include + diff --git a/examples/stm32/f4/stm32f429i-discovery/mandelbrot/README b/examples/stm32/f4/stm32f429i-discovery/mandelbrot/README new file mode 100644 index 0000000..b76cd42 --- /dev/null +++ b/examples/stm32/f4/stm32f429i-discovery/mandelbrot/README @@ -0,0 +1,14 @@ +------------------------------------------------------------------------------ +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) diff --git a/examples/stm32/f4/stm32f429i-discovery/mandelbrot/mandel.c b/examples/stm32/f4/stm32f429i-discovery/mandelbrot/mandel.c new file mode 100644 index 0000000..fd114ec --- /dev/null +++ b/examples/stm32/f4/stm32f429i-discovery/mandelbrot/mandel.c @@ -0,0 +1,125 @@ +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2009 Uwe Hermann + * Copyright (C) 2011 Stephen Caudle + * Copyright (C) 2012 Daniel Serpell + * + * 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 . + */ + +#include +#include +#include + +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; +}