/*
 * 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>
 * Modified by Fernando Cortes <fermando.corcam@gmail.com>
 * modified by Guillermo Rivera <memogrg@gmail.com>
 * modified by Frantisek Burian <BuFran@seznam.cz>
 *
 * 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/adc.h>
#include <libopencm3/stm32/usart.h>
#include <libopencm3/stm32/gpio.h>

uint8_t channel_array[] = { ADC_CHANNEL1, ADC_CHANNEL1, ADC_CHANNEL_TEMP};

static void adc_setup(void)
{
	rcc_periph_clock_enable(RCC_ADC);
	rcc_periph_clock_enable(RCC_GPIOA);

	gpio_mode_setup(GPIOA, GPIO_MODE_ANALOG, GPIO_PUPD_NONE, GPIO0);
	gpio_mode_setup(GPIOA, GPIO_MODE_ANALOG, GPIO_PUPD_NONE, GPIO1);

	adc_power_off(ADC1);
	adc_set_clk_source(ADC1, ADC_CLKSOURCE_ADC);
	adc_calibrate_start(ADC1);
	adc_calibrate_wait_finish(ADC1);
	adc_set_operation_mode(ADC1, ADC_MODE_SCAN);
	adc_disable_external_trigger_regular(ADC1);
	adc_set_right_aligned(ADC1);
	adc_enable_temperature_sensor();
	adc_set_sample_time_on_all_channels(ADC1, ADC_SMPTIME_071DOT5);
	adc_set_regular_sequence(ADC1, 1, channel_array);
	adc_set_resolution(ADC1, ADC_RESOLUTION_12BIT);
	adc_disable_analog_watchdog(ADC1);
	adc_power_on(ADC1);

	/* Wait for ADC starting up. */
	int i;
	for (i = 0; i < 800000; i++) {    /* Wait a bit. */
		__asm__("nop");
	}

}

static void usart_setup(void)
{
	/* Enable clocks for GPIO port A (for GPIO_USART2_TX) and USART1. */
	rcc_periph_clock_enable(RCC_USART1);
	rcc_periph_clock_enable(RCC_GPIOA);

	/* Setup GPIO pin GPIO_USART1_TX/GPIO9 on GPIO port A for transmit. */
	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO9);
	gpio_set_af(GPIOA, GPIO_AF1, GPIO9);

	/* Setup UART parameters. */
	usart_set_baudrate(USART1, 38400);
	usart_set_databits(USART1, 8);
	usart_set_stopbits(USART1, USART_CR2_STOP_1_0BIT);
	usart_set_mode(USART1, USART_MODE_TX);
	usart_set_parity(USART1, USART_PARITY_NONE);
	usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);

	/* Finally enable the USART. */
	usart_enable(USART1);
}

static void my_usart_print_int(uint32_t usart, int16_t value)
{
	int8_t i;
	int8_t nr_digits = 0;
	char buffer[25];

	if (value < 0) {
		usart_send_blocking(usart, '-');
		value = value * -1;
	}

	if (value == 0) {
		usart_send_blocking(usart, '0');
	}

	while (value > 0) {
		buffer[nr_digits++] = "0123456789"[value % 10];
		value /= 10;
	}

	for (i = nr_digits-1; i >= 0; i--) {
		usart_send_blocking(usart, buffer[i]);
	}

	usart_send_blocking(usart, '\r');
	usart_send_blocking(usart, '\n');
}

int main(void)
{
	uint16_t temp;

	adc_setup();
	usart_setup();

	while (1) {
		adc_start_conversion_regular(ADC1);
		while (!(adc_eoc(ADC1)));

		temp = adc_read_regular(ADC1);
		my_usart_print_int(USART1, temp);

		int i;
		for (i = 0; i < 800000; i++) {   /* Wait a bit. */
			__asm__("nop");
		}
	}

	return 0;
}