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[EXAMPLE:F0] Add simple usart example

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This commit is contained in:
BuFran
2013-07-09 23:29:58 +02:00
committed by Piotr Esden-Tempski
parent f176fe59d9
commit 60e08c0591
3 changed files with 119 additions and 0 deletions
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examples/stm32/f0/stm32f0-discovery/usart/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 = usart
LDSCRIPT = ../stm32f0-discovery.ld
include ../../Makefile.include

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examples/stm32/f0/stm32f0-discovery/usart/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This example program sends some characters on USART0 on the
ST STM32F0DISCOVERY eval board.
The terminal settings for the receiving device/PC are 38400 8n1.
The sending is done in a blocking way in the code.

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examples/stm32/f0/stm32f0-discovery/usart/usart.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>
*
* 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 GPIOC clock for LED & USARTs. */
rcc_periph_clock_enable(RCC_GPIOC);
rcc_periph_clock_enable(RCC_GPIOA);
/* Enable clocks for USART2. */
rcc_periph_clock_enable(RCC_USART1);
}
static void usart_setup(void)
{
/* Setup USART2 parameters. */
usart_set_baudrate(USART1, 38400);
usart_set_databits(USART1, 8);
usart_set_parity(USART1, USART_PARITY_NONE);
usart_set_stopbits(USART1, USART_CR2_STOP_1_0BIT);
usart_set_mode(USART1, USART_MODE_TX);
usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
/* Finally enable the USART. */
usart_enable(USART1);
}
static void gpio_setup(void)
{
/* Setup GPIO pin GPIO8/9 on GPIO port C for LEDs. */
gpio_mode_setup(GPIOC, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO8 | GPIO9);
/* Setup GPIO pins for USART2 transmit. */
gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9);
/* Setup USART1 TX pin as alternate function. */
gpio_set_af(GPIOA, GPIO_AF1, GPIO9);
}
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(GPIOC, GPIO8); /* LED on/off */
usart_send_blocking(USART1, c + '0'); /* USART1: Send byte. */
c = (c == 9) ? 0 : c + 1; /* Increment c. */
if ((j++ % 80) == 0) { /* Newline after line full. */
usart_send_blocking(USART1, '\r');
usart_send_blocking(USART1, '\n');
}
for (i = 0; i < 100000; i++) /* Wait a bit. */
__asm__("NOP");
}
return 0;
}