120 lines
3.3 KiB
C
120 lines
3.3 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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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU 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 program 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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/stm32/f1/rcc.h>
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#include <libopencm3/stm32/f1/gpio.h>
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#include <libopencm3/stm32/usart.h>
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#include <libopencm3/stm32/nvic.h>
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void clock_setup(void)
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{
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rcc_clock_setup_in_hse_8mhz_out_72mhz();
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/* Enable GPIOA clock (for LED GPIOs). */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
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/* Enable clocks for GPIO port A (for GPIO_USART1_TX) and USART1. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN |
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RCC_APB2ENR_AFIOEN |
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RCC_APB2ENR_USART1EN);
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}
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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 pin GPIO_USART1_RE_TX on GPIO port B for transmit. */
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gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
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GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
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/* Setup GPIO pin GPIO_USART1_RE_RX on GPIO port B for receive. */
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gpio_set_mode(GPIOA, GPIO_MODE_INPUT,
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GPIO_CNF_INPUT_FLOAT, GPIO_USART1_RX);
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/* Setup UART parameters. */
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usart_set_baudrate(USART1, 230400, rcc_ppre2_frequency);
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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_parity(USART1, USART_PARITY_NONE);
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usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
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usart_set_mode(USART1, USART_MODE_TX_RX);
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/* Enable USART1 Receive interrupt. */
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USART_CR1(USART1) |= USART_CR1_RXNEIE;
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/* Finally enable the USART. */
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usart_enable(USART1);
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}
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void gpio_setup(void)
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{
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gpio_set(GPIOC, GPIO12);
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/* Setup GPIO6 and 7 (in GPIO port A) for led use. */
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gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ,
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GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
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}
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void usart1_isr(void)
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{
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static u8 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(GPIOC, GPIO12);
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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_CR1(USART1) |= USART_CR1_TXEIE;
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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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/* Indicate that we are sending out data. */
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//gpio_toggle(GPIOA, GPIO7);
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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_CR1(USART1) &= ~USART_CR1_TXEIE;
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}
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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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/* Wait forever and do nothing. */
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while (1)
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__asm__("nop");
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return 0;
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}
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