Files
libopencm3-examples/examples/stm32/f0/stm32f0-discovery/usart/usart.c
Karl Palsson be1d296e2f stm32: serial use 115200 baud rate
115200 is a much more sane "default" than 38400.
Instead of a mix of 38400 and 115200, just use 115200 in all places.
There's no reason for modern 32bit cpus to be using such old slow
baudrates.

Tested on f1, f4, l1.  Replaced some old f1 code that predated some
library support code for this.
2019-06-02 20:51:42 +00:00

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 USART2. */
rcc_periph_clock_enable(RCC_USART1);
}
static void usart_setup(void)
{
/* Setup USART2 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 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;
}