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add basic DCF77 pulse detection

This commit is contained in:
King Kévin 2016-05-05 18:03:07 +02:00
parent ad84ae1874
commit 5a43d4d48c
2 changed files with 163 additions and 0 deletions
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110
lib/rtc_dcf77.c Normal file
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/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/** @brief library to get time from a DCF77 module
* @file rtc_dcf77.c
* @author King Kévin <kingkevin@cuvoodoo.info>
* @date 2016
* @note peripherals used: GPIO @ref rtc_dcf77_gpio, timer @ref rtc_dcf77_timer
*/
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // general utilities
#include <stdio.h>
/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/stm32/spi.h> // SPI library
#include <libopencm3/stm32/timer.h> // timer library
#include <libopencm3/cm3/nvic.h> // interrupt handler
#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
#include "rtc_dcf77.h" // RTC DCF77 library API
#include "global.h" // common methods
volatile bool rtc_dcf77_time_flag = false;
void rtc_dcf77_setup(void)
{
// setup enable output
rcc_periph_clock_enable(RTC_DCF77_ENABLE_RCC); // enable clock GPIO peripherial
gpio_set_mode(RTC_DCF77_ENABLE_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, RTC_DCF77_ENABLE_PIN); // set pin to output push-pull to be able to enable the module
rtc_dcf77_off(); // disable module at start
// setup signal input
rcc_periph_clock_enable(RTC_DCF77_SIGNAL_RCC); // enable clock for signal input peripheral
gpio_set_mode(RTC_DCF77_SIGNAL_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, RTC_DCF77_SIGNAL_PIN); // set signal pin to input
rcc_periph_clock_enable(RCC_AFIO); // enable alternate function clock for external interrupt
exti_select_source(RTC_DCF77_SIGNAL_EXTI, RTC_DCF77_SIGNAL_PORT); // mask external interrupt of this pin only for this port
exti_set_trigger(RTC_DCF77_SIGNAL_EXTI, EXTI_TRIGGER_BOTH); // trigger on both edges
exti_enable_request(RTC_DCF77_SIGNAL_EXTI); // enable external interrupt
nvic_enable_irq(RTC_DCF77_SIGNAL_IRQ); // enable interrupt
// setup timer to measure pulses
rcc_periph_clock_enable(RTC_DCF77_TIMER_RCC); // enable clock for timer peripheral
timer_reset(RTC_DCF77_TIMER); // reset timer state
timer_set_mode(RTC_DCF77_TIMER, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
timer_set_prescaler(RTC_DCF77_TIMER, RTC_DCF77_TIMER_MAX_TIME*(rcc_ahb_frequency/1000)/(1<<16)); // set prescaler to count up to the maximum time
timer_enable_counter(RTC_DCF77_TIMER); // start timer to measure time
}
void rtc_dcf77_on(void)
{
gpio_clear(RTC_DCF77_ENABLE_PORT, RTC_DCF77_ENABLE_PIN); // enable module by pull pin low
}
void rtc_dcf77_off(void)
{
gpio_set(RTC_DCF77_ENABLE_PORT, RTC_DCF77_ENABLE_PIN); // disable module by pull pin high
}
/** @brief interrupt service routine called when signal edge is detected */
void RTC_DCF77_SIGNAL_ISR(void)
{
exti_reset_request(RTC_DCF77_SIGNAL_EXTI); // reset interrupt
static uint16_t old_state = 0; // save last port state to detect difference
static uint8_t pulse = 0; // next pulse number in the DCF77 frame
//static uint16_t pulse_rising = 0, pulse_falling = 0; // time on when the last pulse edge has been detected
static uint16_t pulse_rising = 0;
uint16_t time = timer_get_counter(RTC_DCF77_TIMER); // get timer value
uint16_t new_state = gpio_get(RTC_DCF77_SIGNAL_PORT, RTC_DCF77_SIGNAL_PIN); // save last port state to detect difference
if (old_state!=new_state) { // pulse edge detected
if (new_state) { // rising edge
time = (uint32_t)(time-pulse_rising)*RTC_DCF77_TIMER_MAX_TIME/(1<<16); // get time since last rising edge (integer underflow possible)
if (time < 900) { // ignore glitches
goto end;
} else if (time < 1100) { // a normal pulse
pulse = (pulse+1)%59; // go to next pulse (there should be no more than 59)
} else if (time < 1900) { // ignore glitch
goto end;
} else if (time < 2100) { // first pulse of a frame
pulse = 0;
} else { // something is wrong, restart
pulse = 0;
}
led_toggle();
pulse_rising = 0; // save new edge
timer_set_counter(RTC_DCF77_TIMER, 0); // reset timer to count
printf("%u\n", pulse);
}
}
end:
old_state = new_state; // save new state
}

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lib/rtc_dcf77.h Normal file
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/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/** @brief library to get time from a DCF77 module
* @file rtc_dcf77.h
* @author King Kévin <kingkevin@cuvoodoo.info>
* @date 2016
* @note peripherals used: GPIO @ref rtc_dcf77_gpio, timer @ref rtc_dcf77_timer
*/
#pragma once
/** @defgroup rtc_dcf77_gpio output to enable DCF module and input to capture DCF signal
* @{
*/
#define RTC_DCF77_ENABLE_RCC RCC_GPIOA /**< GPIO peripheral clock to enable the module */
#define RTC_DCF77_ENABLE_PORT GPIOA /**< GPIO port to enable the module */
#define RTC_DCF77_ENABLE_PIN GPIO2 /**< GPIO pinto enable the module */
#define RTC_DCF77_SIGNAL_RCC RCC_GPIOA /**< GPIO peripheral clock to capture the DCF signal */
#define RTC_DCF77_SIGNAL_PORT GPIOA /**< GPIO port to capture the DCF signal */
#define RTC_DCF77_SIGNAL_PIN GPIO3 /**< GPIO pin to capture the DCF signal */
#define RTC_DCF77_SIGNAL_EXTI EXTI3 /**< GPIO external interrupt to capture the DCF signal */
#define RTC_DCF77_SIGNAL_IRQ NVIC_EXTI3_IRQ /**< GPIO line interrupt */
#define RTC_DCF77_SIGNAL_ISR exti3_isr /**< GPIO line interrupt service routine */
/** @} */
/** @defgroup rtc_dcf77_timer timer to measure signal puls
* @{
*/
#define RTC_DCF77_TIMER TIM4 /**< timer peripheral */
#define RTC_DCF77_TIMER_RCC RCC_TIM4 /**< timer peripheral clock */
#define RTC_DCF77_TIMER_MAX_TIME 2200 /**< the maximum time in ms the timer can count. DCF77 have pulses < 2s */
/** @} */
/** @brief set when time information has been received */
extern volatile bool rtc_dcf77_time_flag;
/** @brief setup DCF77 time receiver module */
void rtc_dcf77_setup(void);
/** @brief switch on DCF77 time receiver module */
void rtc_dcf77_on(void);
/** @brief switch off DCF77 time receiver module */
void rtc_dcf77_off(void);