From 25d1f4326cce046b245cd224f3e6335c1a6f76b0 Mon Sep 17 00:00:00 2001
From: Max Christian Pohle
Date: Thu, 25 May 2017 19:45:15 +0200
Subject: DCF signal recognized and shown

---
 inc/int/dcf77.c | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 inc/int/dcf77.h |  69 ++++++++++++++++++++++++++++
 2 files changed, 208 insertions(+)
 create mode 100755 inc/int/dcf77.c
 create mode 100755 inc/int/dcf77.h

(limited to 'inc')

diff --git a/inc/int/dcf77.c b/inc/int/dcf77.c
new file mode 100755
index 0000000..13af50d
--- /dev/null
+++ b/inc/int/dcf77.c
@@ -0,0 +1,139 @@
+// vim:set et sw=2 ts=2 tw=120:
+#include "dcf77.h"
+
+// returns -1 on error
+unsigned char getBits(const DCF start, const char len)
+{
+  static const unsigned char mult[]  = {1, 2, 4, 8, 10, 20 ,40 ,80};
+  /// unsigned char p = 1; //parity
+  unsigned char r = 0; // retval
+  unsigned char i;
+  for(i=0; i<len; i++)
+    r += dcf77[start+i].bit * mult[i];
+    /// if(dcf77[start+i].bit)
+      /// p ^= 1;
+  return r;
+}
+
+void set_dcf_value()
+{
+  t_current.m = (getBits(DCF_MIN,      7)) - 1;
+  t_current.h = (getBits(DCF_HOUR,     6));
+  t_current.dd = (getBits(DCF_DAY,     6));
+  t_current.wd = (getBits(DCF_WEEKDAY, 3));
+  t_current.mm = (getBits(DCF_MONTH,   5));
+  t_current.yy = (getBits(DCF_YEAR,    8));
+}
+
+// 7372800/a=10000
+// 115200 / a * x = 10000
+// 7372800/8/150
+
+// interrupt service routine (ISR) for timer 0 A compare match
+/*
+ISR(TIMER0A_COMP_vect) // called 10000 times per second (12000000/8/150)
+{
+
+}
+*/
+ISR(TIMER0_COMPB_vect)
+{
+
+}
+
+ISR(TIMER0_COMPA_vect)
+{
+  interval++;
+  if (++t_current.ms >= 1000) // one second
+  {
+    t_current.ms = 0; // restart
+    if (++t_current.s > 59) // one minute
+    {
+      t_current.s = 0; // restart
+      if (++t_current.m > 59) // one hour
+      {
+        t_current.m = 0; // restart
+        if (++t_current.h > 23) // one day
+        {
+          t_current.h = 0; // restart
+          t_current.dd++;
+        }
+      }
+    }
+  }
+}
+
+ISR(INT0_vect)
+{
+}
+
+ISR(PCINT0_vect)
+{
+  interval = 1;
+  /// stdout_put_int(interval, uart_putc);
+  /// stdout_put_string("INT0 call\n", uart_putc);
+  // cli();
+
+  // if(INT0_CONTROL == INT0_RISING_EDGE)
+  // if(MCUCR & (1<<ISC00))
+  // {
+  if (interval > 1000 && interval < 2000) // 59th second - no rising edge at the beginning
+  {
+    /// if(dcf77_bit == 59) // check if every bit has been transfered
+    // set_dcf_value();  // completely received- apply new time data
+
+    // 59th second: synchronize with receiver...
+    TCNT0 = 0;
+    dcf77_bit = 0;
+    t_current.s = 0;
+    t_current.ms = 0;
+    // t_current.us = 0;
+    // falling edge causes interrupt...
+    // MCUCR &= ~(1 << ISC00);
+    // MCUCR |=  (1 << ISC01);
+    // INT0_CONTROL = INT0_FALLING_EDGE;
+  }
+  else // INT0_FALLING_EDGE
+  {
+    dcf77[dcf77_bit++].bit = interval >= 200 ? 1 : 0;
+
+    // rising edge causes interrupt...
+    // MCUCR |= (1 << ISC00);
+    // MCUCR |= (1 << ISC01);
+    // INT0_CONTROL = INT0_RISING_EDGE;
+    // interval = 0; // reset interval to count next interval
+  }
+
+  interval = 0;
+  // sei();
+}
+
+/*
+void timer_init()
+{
+  // 7372800/8
+  // >>>>>> DDRD &= ~((1<<PD2) | (1<<PD3)); // make INT0 and INT1 input-pins
+
+  // Prescaler...
+  // output compare...
+
+  //OCR0   = 152 - 1;
+  //TCCR0 |= (0<<WGM01) | (1<<WGM01);
+
+  // ICNC1 (Input Capture Noise Canceler (4 CKs) Timer/Counter 1
+  // ICES1 (Input Capture Edge Select Timer/Counter 1) - 1:increasing 0:falling
+  // CSx: set prescaler (010 means 8)
+  /// TCCR1B = (1<<ICNC1) | (1<<ICES1) | (0<<CS12) | (1<<CS11) | (0<<CS10);
+  // OCIE0: Output Compare Match Interrupt Enable
+  // TICIE: Timer/Counter Input Capture Interrupt Enable
+
+  // interrupts_init...
+  // General Interrupt Mask Register (enables interrupts)
+  GIMSK |= (1<<INT0);
+  // GICR |= (1<<INT0);
+  // MCU Control Register (controls CPU-behaviours like interrupts & sleepmode)
+  MCUCR |= (1<<ISC01) | (1<<ISC00); // any logical change generates interrupt
+  INT0_CONTROL = INT0_RISING_EDGE; // going to toggle int0-behaviour
+  /// loworhigh.bit = 0;
+}
+*/
diff --git a/inc/int/dcf77.h b/inc/int/dcf77.h
new file mode 100755
index 0000000..e47ca4e
--- /dev/null
+++ b/inc/int/dcf77.h
@@ -0,0 +1,69 @@
+#ifndef CLOCK_H
+#define CLOCK_H
+  /* this dcf77-module relies on a accuarate clock (crystal) for receiving
+   * the dcf-signal. therefor the clock is going to work as expected,
+   * even with no dcf77-signal available.
+   * receivement is automatically turned on, if the avr is connected to the
+   * signal via INT0. if there is no signal the clock will not be set (K.I.S.S.)
+   *
+   */
+  #include <avr/io.h>
+  #include <avr/interrupt.h>
+
+  #include <stdint.h>
+
+  #define INT0_CONTROL       MCUCR
+  // #define INT0_FALLING_EDGE  0x02
+  // #define INT0_RISING_EDGE   0x03
+  #define INT0_FALLING_EDGE  (1<<ISC01)
+  #define INT0_RISING_EDGE   (1<<ISC01 | 1<<ISC00)
+  #define INT0_EDGE_ANY      (1<<ISC00)
+
+  typedef struct
+  {
+    volatile unsigned char bit : 1;
+  } Bit;
+
+  typedef struct
+  {
+    uint16_t h ;  // hour
+    uint16_t m ;  // minute
+    uint16_t s ;  // second
+    uint16_t ms;  // milli second
+    uint8_t yy;  // year
+    uint8_t mm;  // month
+    uint8_t dd;  // day
+    uint8_t wd;  // weekday
+  } Time;
+
+  typedef enum
+  {
+    DCF_FIRST   = 0,  // start of a new minute (note: always 0)
+    DCF_WEATHER = 14, // proprietary :-(
+    DCF_ANTENNA = 15, // 0: normal, 1: replacement
+    DCF_DST     = 16, // daylight saving time: this hour new time...
+    DCF_MEZ     = 17, // 'summer-time'
+    DCF_MESZ    = 18, // 'winter-time'
+    DCF_DBLSEC  = 19, // one extra second gonna be inserted
+    DCF_START   = 20, // begin of time-info (note: always 1)
+    DCF_MIN     = 21, // 7 bit
+    DCF_MINP    = 28, // parity bit for minutes
+    DCF_HOUR    = 29, // 6 bit
+    DCF_HOURP   = 35, // parity bit for hours
+    DCF_DAY     = 36, // 6 bit
+    DCF_WEEKDAY = 42, // 3 bit
+    DCF_MONTH   = 45, // 5 bit
+    DCF_YEAR    = 50, // 8 bit
+    DCF_DATEP   = 58  // parity bit for date
+  } DCF;
+
+  volatile Bit dcf77[60];
+  volatile uint8_t dcf77_bit;
+  volatile Time t_current;
+  volatile uint16_t interval;
+
+  /// void getBits(volatile unsigned char* target, const DCF start, const char len, const DCF parity);
+  /// void set_dcf_value();
+  /// void interrupts_init();
+
+#endif
-- 
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