Files
libopencm3-examples/examples/stm32/f0/stm32f0-discovery/usart/usart.c

85 lines
2.4 KiB
C

/*
* 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 USART. */
rcc_periph_clock_enable(RCC_USART1);
}
static void usart_setup(void)
{
/* Setup USART parameters. */
usart_set_baudrate(USART1, 115200);
usart_set_databits(USART1, 8);
usart_set_parity(USART1, USART_PARITY_NONE);
usart_set_stopbits(USART1, USART_CR2_STOPBITS_1);
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 USART transmit. */
gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9);
/* Setup USART 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 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;
}