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[stm32f429i-discovery] Added usart example.

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This commit is contained in:
Piotr Esden-Tempski
2015-01-14 18:03:21 -08:00
parent ae17f5a77b
commit 23c29f1784
3 changed files with 128 additions and 0 deletions
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25
examples/stm32/f4/stm32f429i-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 = ../stm32f429i-discovery.ld
include ../../Makefile.include

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examples/stm32/f4/stm32f429i-discovery/usart/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This example program sends repeating sequence of characters "0123456789" on
USART1 on the ST STM32F429IDISCOVERY eval board.
The sending is done in a blocking way.
Board connections:
------------------
PA9 (USART1_TX) TTL serial output (38400,8,N,1)
Notes:
------
You can connect the UART to the stlink by closing the SB11 and SB15 solder
jumpers.

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examples/stm32/f4/stm32f429i-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 GPIOG clock for LED & USARTs. */
rcc_periph_clock_enable(RCC_GPIOG);
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_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);
}
int main(void)
{
int i, j = 0, c = 0;
clock_setup();
gpio_setup();
usart_setup();
/* Blink the LED (PG13) on the board with every transmitted byte. */
while (1) {
gpio_toggle(GPIOG, GPIO13); /* 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 < 3000000; i++) { /* Wait a bit. */
__asm__("NOP");
}
}
return 0;
}