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[EXAMPLE:F0] Add simple ADC example

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This commit is contained in:
Frantisek Burian
2013-12-14 19:18:22 +01:00
committed by Piotr Esden-Tempski
parent 4ae45b913d
commit c5d6480201
3 changed files with 166 additions and 0 deletions
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examples/stm32/f0/stm32f0-discovery/adc/Makefile Normal file
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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/>.
##
BINARY = adc
LDSCRIPT = ../stm32f0-discovery.ld
include ../../Makefile.include

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examples/stm32/f0/stm32f0-discovery/adc/README Normal file
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------------------------------------------------------------------------------
README
------------------------------------------------------------------------------
This is the smallest-possible example program using libopencm3.
It's intended for the ST STM32F0DISCOVERY eval board. It should read from the
ADC_IN1 (PA1) pin its voltage and print it to the serial port on pin PA9 with
parameters (38400,8,N,1)

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examples/stm32/f0/stm32f0-discovery/adc/adc.c Normal file
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/*
* 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;
}