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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/>.
 */

#include <libopencm3/stm32/f1/rcc.h>
#include <libopencm3/stm32/f1/gpio.h>
#include <libopencm3/stm32/usart.h>

static void clock_setup(void)
{
	rcc_clock_setup_in_hse_12mhz_out_72mhz();

	/* Enable GPIOA, GPIOB, GPIOC clock. */
	rcc_peripheral_enable_clock(&RCC_APB2ENR,
				    RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN |
				    RCC_APB2ENR_IOPCEN);

	/* Enable clocks for GPIO port B (for GPIO_USART3_TX) and USART3. */
	rcc_peripheral_enable_clock(&RCC_APB1ENR,
				    RCC_APB1ENR_USART2EN);
}

static void usart_setup(void)
{
	/* Setup GPIO pin GPIO_USART2_TX. */
	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
		      GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX);

	/* Setup UART parameters. */
	usart_set_baudrate(USART2, 38400);
	usart_set_databits(USART2, 8);
	usart_set_stopbits(USART2, USART_STOPBITS_1);
	usart_set_mode(USART2, USART_MODE_TX);
	usart_set_parity(USART2, USART_PARITY_NONE);
	usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE);

	/* Finally enable the USART. */
	usart_enable(USART2);

}

static void gpio_setup(void)
{
	/* Set GPIO8 (in GPIO port A) to 'output push-pull'. */
	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_2_MHZ,
		      GPIO_CNF_OUTPUT_PUSHPULL, GPIO8);
}

int main(void)
{
	int i, j = 0, c = 0;

	clock_setup();
	gpio_setup();
	usart_setup();

	/* Blink the LED (PA8) on the board with every transmitted byte. */
	while (1) {
		gpio_toggle(GPIOA, GPIO8);	/* LED on/off */
		usart_send_blocking(USART2, c + '0');	/* USART2: Send byte. */
		c = (c == 9) ? 0 : c + 1;	/* Increment c. */
		if ((j++ % 80) == 0) {	/* Newline after line full. */
			usart_send_blocking(USART2, '\r');
			usart_send_blocking(USART2, '\n');
		}
		for (i = 0; i < 800000; i++)	/* Wait a bit. */
			__asm__("nop");
	}

	return 0;
}