116 lines
3.2 KiB
C
116 lines
3.2 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
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* Copyright (C) 2011 Stephen Caudle <scaudle@doceme.com>
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* Copyright (C) 2013-2015 Piotr Esden-Tempski <piotr@esden.net>
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*
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* This library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/stm32/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/usart.h>
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#include <libopencm3/cm3/nvic.h>
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static void clock_setup(void)
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{
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/* Enable GPIOG clock for LED & USARTs. */
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rcc_periph_clock_enable(RCC_GPIOG);
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rcc_periph_clock_enable(RCC_GPIOA);
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/* Enable clocks for USART1. */
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rcc_periph_clock_enable(RCC_USART1);
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}
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static void usart_setup(void)
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{
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/* Enable the USART1 interrupt. */
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nvic_enable_irq(NVIC_USART1_IRQ);
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/* Setup GPIO pins for USART1 transmit. */
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gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9);
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/* Setup GPIO pins for USART1 receive. */
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gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO10);
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gpio_set_output_options(GPIOA, GPIO_OTYPE_OD, GPIO_OSPEED_25MHZ, GPIO10);
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/* Setup USART1 TX and RX pin as alternate function. */
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gpio_set_af(GPIOA, GPIO_AF7, GPIO9);
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gpio_set_af(GPIOA, GPIO_AF7, GPIO10);
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/* Setup USART1 parameters. */
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usart_set_baudrate(USART1, 38400);
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usart_set_databits(USART1, 8);
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usart_set_stopbits(USART1, USART_STOPBITS_1);
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usart_set_mode(USART1, USART_MODE_TX_RX);
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usart_set_parity(USART1, USART_PARITY_NONE);
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usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
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/* Enable USART1 Receive interrupt. */
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usart_enable_rx_interrupt(USART1);
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/* Finally enable the USART. */
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usart_enable(USART1);
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}
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static void gpio_setup(void)
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{
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/* Setup GPIO pin GPIO13 on GPIO port G for LED. */
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gpio_mode_setup(GPIOG, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO13);
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}
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int main(void)
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{
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clock_setup();
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gpio_setup();
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usart_setup();
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while (1) {
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__asm__("NOP");
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}
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return 0;
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}
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void usart1_isr(void)
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{
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static uint8_t data = 'A';
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/* Check if we were called because of RXNE. */
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if (((USART_CR1(USART1) & USART_CR1_RXNEIE) != 0) &&
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((USART_SR(USART1) & USART_SR_RXNE) != 0)) {
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/* Indicate that we got data. */
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gpio_toggle(GPIOG, GPIO13);
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/* Retrieve the data from the peripheral. */
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data = usart_recv(USART1);
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/* Enable transmit interrupt so it sends back the data. */
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usart_enable_tx_interrupt(USART1);
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}
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/* Check if we were called because of TXE. */
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if (((USART_CR1(USART1) & USART_CR1_TXEIE) != 0) &&
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((USART_SR(USART1) & USART_SR_TXE) != 0)) {
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/* Put data into the transmit register. */
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usart_send(USART1, data);
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/* Disable the TXE interrupt as we don't need it anymore. */
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usart_disable_tx_interrupt(USART1);
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}
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}
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