From aac5909ff133a71dc01037712f86e89f4e7877d7 Mon Sep 17 00:00:00 2001 From: Daniel Serpell Date: Wed, 22 Aug 2012 00:05:10 -0400 Subject: Add a floating-point example to the stm32f4. This example calculates a mandelbrot fractal using floating point in C. --- .../stm32/f4/stm32f4-discovery/mandelbrot/Makefile | 25 ++++ .../stm32/f4/stm32f4-discovery/mandelbrot/README | 12 ++ .../stm32/f4/stm32f4-discovery/mandelbrot/mandel.c | 127 +++++++++++++++++++++ 3 files changed, 164 insertions(+) create mode 100644 examples/stm32/f4/stm32f4-discovery/mandelbrot/Makefile create mode 100644 examples/stm32/f4/stm32f4-discovery/mandelbrot/README create mode 100644 examples/stm32/f4/stm32f4-discovery/mandelbrot/mandel.c diff --git a/examples/stm32/f4/stm32f4-discovery/mandelbrot/Makefile b/examples/stm32/f4/stm32f4-discovery/mandelbrot/Makefile new file mode 100644 index 0000000..3879eca --- /dev/null +++ b/examples/stm32/f4/stm32f4-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 = ../stm32f4-discovery.ld + +include ../../Makefile.include + diff --git a/examples/stm32/f4/stm32f4-discovery/mandelbrot/README b/examples/stm32/f4/stm32f4-discovery/mandelbrot/README new file mode 100644 index 0000000..fe4fb13 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/mandelbrot/README @@ -0,0 +1,12 @@ +------------------------------------------------------------------------------ +README +------------------------------------------------------------------------------ + +This example program demonstrates the floating point coprocessor usage on +the ST STM32F4DISCOVERY eval board. + +A mandelbrot fractal is calculated and sent as "ascii-art" image through +the USART2. + +The terminal settings for the receiving device/PC are 38400 8n1. + diff --git a/examples/stm32/f4/stm32f4-discovery/mandelbrot/mandel.c b/examples/stm32/f4/stm32f4-discovery/mandelbrot/mandel.c new file mode 100644 index 0000000..5cbdafd --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/mandelbrot/mandel.c @@ -0,0 +1,127 @@ +/* + * 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 + +void clock_setup(void) +{ + /* Enable high-speed clock at 120MHz */ + rcc_clock_setup_hse_3v3(&hse_8mhz_3v3[CLOCK_3V3_120MHZ]); + + /* Enable GPIOD clock for LED & USARTs. */ + rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPDEN); + rcc_peripheral_enable_clock(&RCC_AHB1ENR, RCC_AHB1ENR_IOPAEN); + + /* Enable clocks for USART2. */ + rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN); +} + +void usart_setup(void) +{ + /* Setup USART2 parameters. */ + usart_set_baudrate(USART2, 38400); + usart_set_databits(USART2, 8); + usart_set_stopbits(USART2, USART_STOPBITS_1); + usart_set_mode(USART2, USART_MODE_TX); + usart_set_parity(USART2, USART_PARITY_NONE); + usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE); + + /* Finally enable the USART. */ + usart_enable(USART2); +} + +void gpio_setup(void) +{ + /* Setup GPIO pin GPIO12 on GPIO port D for LED. */ + gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO12); + + /* Setup GPIO pins for USART2 transmit. */ + gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO2); + + /* Setup USART2 TX pin as alternate function. */ + gpio_set_af(GPIOA, GPIO_AF7, GPIO2); +} + +/* 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 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(USART2, color[i]); + } + usart_send_blocking(USART2, '\r'); + usart_send_blocking(USART2, '\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 (PD12) on the board with each fractal drawn. */ + gpio_toggle(GPIOD, GPIO12); /* 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(USART2, '\r'); + usart_send_blocking(USART2, '\n'); + } + + return 0; +} -- cgit v1.2.3