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[stm32f429i-discovery] Added USART IRQ example.

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Piotr Esden-Tempski
2015-01-14 18:14:40 -08:00
parent 23c29f1784
commit 7bf64424ab
3 changed files with 159 additions and 0 deletions
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examples/stm32/f4/stm32f429i-discovery/usart_irq/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_irq
LDSCRIPT = ../stm32f429i-discovery.ld
include ../../Makefile.include

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examples/stm32/f4/stm32f429i-discovery/usart_irq/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This example program echoes data sent in on USART1 on the
ST STM32F429IDISCOVERY eval board. Uses interrupts for that purpose.
The sending is done in a nonblocking way.
Board connections:
------------------
PA9 (USART1_TX) TTL serial output (38400,8,N,1)
PA10 (USART1_RX) TTL serial input (38400,8,N,1)
Notes:
------
You can connect the USART to the stlink by closing the SB11 and SB15 jumpers.

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examples/stm32/f4/stm32f429i-discovery/usart_irq/usart_irq.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>
* Copyright (C) 2013 Piotr Esden-Tempski <piotr@esden.net>
*
* 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>
#include <libopencm3/cm3/nvic.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 USART1. */
rcc_periph_clock_enable(RCC_USART1);
}
static void usart_setup(void)
{
/* Enable the USART1 interrupt. */
nvic_enable_irq(NVIC_USART1_IRQ);
/* Setup GPIO pins for USART1 transmit. */
gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9);
/* Setup GPIO pins for USART1 receive. */
gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO10);
gpio_set_output_options(GPIOA, GPIO_OTYPE_OD, GPIO_OSPEED_25MHZ, GPIO10);
/* Setup USART1 TX and RX pin as alternate function. */
gpio_set_af(GPIOA, GPIO_AF7, GPIO9);
gpio_set_af(GPIOA, GPIO_AF7, GPIO10);
/* Setup USART1 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_RX);
usart_set_parity(USART1, USART_PARITY_NONE);
usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
/* Enable USART1 Receive interrupt. */
usart_enable_rx_interrupt(USART1);
/* 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);
}
int main(void)
{
clock_setup();
gpio_setup();
usart_setup();
while (1) {
__asm__("NOP");
}
return 0;
}
void usart1_isr(void)
{
static uint8_t data = 'A';
/* Check if we were called because of RXNE. */
if (((USART_CR1(USART1) & USART_CR1_RXNEIE) != 0) &&
((USART_SR(USART1) & USART_SR_RXNE) != 0)) {
/* Indicate that we got data. */
gpio_toggle(GPIOG, GPIO13);
/* Retrieve the data from the peripheral. */
data = usart_recv(USART1);
/* Enable transmit interrupt so it sends back the data. */
usart_enable_tx_interrupt(USART1);
}
/* Check if we were called because of TXE. */
if (((USART_CR1(USART1) & USART_CR1_TXEIE) != 0) &&
((USART_SR(USART1) & USART_SR_TXE) != 0)) {
/* Put data into the transmit register. */
usart_send(USART1, data);
/* Disable the TXE interrupt as we don't need it anymore. */
usart_disable_tx_interrupt(USART1);
}
}