84 lines
2.5 KiB
C
84 lines
2.5 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/rcc.h>
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#include <libopencm3/stm32/gpio.h>
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#include <libopencm3/stm32/usart.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 GPIOC clock. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
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/* Enable clocks for GPIO port B (for GPIO_USART3_TX) and USART3. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPBEN);
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rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART3EN);
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}
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void usart_setup(void)
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{
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/* Setup GPIO pin GPIO_USART3_TX/GPIO10 on GPIO port B for transmit. */
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gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ,
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GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART3_TX);
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/* Setup UART parameters. */
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usart_set_baudrate(USART3, 38400);
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usart_set_databits(USART3, 8);
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usart_set_stopbits(USART3, USART_STOPBITS_1);
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usart_set_mode(USART3, USART_MODE_TX);
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usart_set_parity(USART3, USART_PARITY_NONE);
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usart_set_flow_control(USART3, USART_FLOWCONTROL_NONE);
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/* Finally enable the USART. */
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usart_enable(USART3);
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}
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void gpio_setup(void)
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{
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/* Set GPIO12 (in GPIO port C) to 'output push-pull'. */
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gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
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GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
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}
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int main(void)
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{
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int i, j = 0, c = 0;
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clock_setup();
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gpio_setup();
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usart_setup();
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/* Blink the LED (PC12) on the board with every transmitted byte. */
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while (1) {
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gpio_toggle(GPIOC, GPIO12); /* LED on/off */
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usart_send_blocking(USART3, c + '0'); /* USART3: Send byte. */
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c = (c == 9) ? 0 : c + 1; /* Increment c. */
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if ((j++ % 80) == 0) { /* Newline after line full. */
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usart_send_blocking(USART3, '\r');
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usart_send_blocking(USART3, '\n');
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}
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for (i = 0; i < 800000; i++) /* Wait a bit. */
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__asm__("NOP");
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}
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return 0;
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}
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