From 3c9ba2ac2d51bb182ca85410021ab95b54ae4275 Mon Sep 17 00:00:00 2001 From: Stephen Caudle Date: Wed, 2 Nov 2011 22:50:49 -0400 Subject: Add usart example for STM32F4 discovery board --- examples/stm32/f4/stm32f4-discovery/usart/Makefile | 23 ++++++ examples/stm32/f4/stm32f4-discovery/usart/README | 11 +++ examples/stm32/f4/stm32f4-discovery/usart/usart.c | 87 ++++++++++++++++++++++ examples/stm32/f4/stm32f4-discovery/usart/usart.ld | 32 ++++++++ 4 files changed, 153 insertions(+) create mode 100644 examples/stm32/f4/stm32f4-discovery/usart/Makefile create mode 100644 examples/stm32/f4/stm32f4-discovery/usart/README create mode 100644 examples/stm32/f4/stm32f4-discovery/usart/usart.c create mode 100644 examples/stm32/f4/stm32f4-discovery/usart/usart.ld (limited to 'examples') diff --git a/examples/stm32/f4/stm32f4-discovery/usart/Makefile b/examples/stm32/f4/stm32f4-discovery/usart/Makefile new file mode 100644 index 0000000..2c1e1b1 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart/Makefile @@ -0,0 +1,23 @@ +## +## This file is part of the libopencm3 project. +## +## Copyright (C) 2009 Uwe Hermann +## +## This program is free software: you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation, either version 3 of the License, or +## (at your option) any later version. +## +## This program 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 General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with this program. If not, see . +## + +BINARY = usart + +include ../../Makefile.include + diff --git a/examples/stm32/f4/stm32f4-discovery/usart/README b/examples/stm32/f4/stm32f4-discovery/usart/README new file mode 100644 index 0000000..168b364 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart/README @@ -0,0 +1,11 @@ +------------------------------------------------------------------------------ +README +------------------------------------------------------------------------------ + +This example program sends some characters on USART2 on the +ST STM32F4DISCOVERY eval board. + +The terminal settings for the receiving device/PC are 38400 8n1. + +The sending is done in a blocking way in the code. + diff --git a/examples/stm32/f4/stm32f4-discovery/usart/usart.c b/examples/stm32/f4/stm32f4-discovery/usart/usart.c new file mode 100644 index 0000000..c8ca2a3 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart/usart.c @@ -0,0 +1,87 @@ +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2009 Uwe Hermann + * Copyright (C) 2011 Stephen Caudle + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +#include +#include +#include + +void clock_setup(void) +{ + /* 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, rcc_ppre1_frequency); + 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); +} + +int main(void) +{ + int i, j = 0, c = 0; + + clock_setup(); + gpio_setup(); + usart_setup(); + + /* Blink the LED (PD12) on the board with every transmitted byte. */ + while (1) { + gpio_toggle(GPIOD, GPIO12); /* LED on/off */ + usart_send_blocking(USART2, c + '0'); /* USART2: Send byte. */ + c = (c == 9) ? 0 : c + 1; /* Increment c. */ + if ((j++ % 80) == 0) { /* Newline after line full. */ + usart_send_blocking(USART2, '\r'); + usart_send_blocking(USART2, '\n'); + } + for (i = 0; i < 3000000; i++) /* Wait a bit. */ + __asm__("NOP"); + } + + return 0; +} diff --git a/examples/stm32/f4/stm32f4-discovery/usart/usart.ld b/examples/stm32/f4/stm32f4-discovery/usart/usart.ld new file mode 100644 index 0000000..1cb43c6 --- /dev/null +++ b/examples/stm32/f4/stm32f4-discovery/usart/usart.ld @@ -0,0 +1,32 @@ +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2009 Uwe Hermann + * Copyright (C) 2011 Stephen Caudle + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +/* Linker script for ST STM32F4DISCOVERY (STM32F407VG, 1024K flash, 128K RAM). */ + +/* Define memory regions. */ +MEMORY +{ + rom (rx) : ORIGIN = 0x08000000, LENGTH = 1024K + ram (rwx) : ORIGIN = 0x20000000, LENGTH = 128K +} + +/* Include the common ld script. */ +INCLUDE libopencm3_stm32f4.ld + -- cgit v1.2.3