From 75a61c57fb0402f777bfa828dd71818a97ed54a4 Mon Sep 17 00:00:00 2001
From: David Lamparter <equinox@diac24.net>
Date: Sun, 1 Apr 2012 00:20:25 +0200
Subject: original dcf77 C code

---
 dcf77.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 dcf77.c

(limited to 'dcf77.c')

diff --git a/dcf77.c b/dcf77.c
new file mode 100644
index 0000000..91ae618
--- /dev/null
+++ b/dcf77.c
@@ -0,0 +1,100 @@
+/************************************************************************/
+/*									*/
+/*			Decode DCF77 Time Information			*/
+/*									*/
+/*              Author: Peter Dannegger                                 */
+/*                      danni@specs.de                                  */
+/*                                                                      */
+/************************************************************************/
+
+
+#include "main.h"
+#include "clock.h"
+#include "timebase.h"
+#include "dcf77.h"
+
+
+  u8 code BITNO[] = {
+    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,		// minute
+    0xFF,						// parity
+    0x10, 0x11, 0x12, 0x13, 0x14, 0x15,			// hour
+    0xFF,						// parity
+    0x20, 0x21, 0x22, 0x23, 0x24, 0x25,			// day
+    0x30, 0x31, 0x32,					// weekday
+    0x40, 0x41, 0x42, 0x43, 0x44,			// month
+    0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,	// year
+    0xFF };						// parity
+  u8 code BMASK[] = { 1, 2, 4, 8, 10, 20, 40, 80 };
+
+
+struct time newtime;
+
+u8 dcf77error = 0;
+u8 synchronize = 0;				// successful recieved
+
+
+void decode_dcf77( u8 pulse )
+{
+  static u8 parity = 0;
+  u8 i;
+  u8 *d;
+
+  i = newtime.second - 21;
+  if( i >= sizeof( BITNO ))			// only bit 21 ... 58
+    return;
+  parity ^= pulse;				// calculate parity
+  i = LPM(&BITNO[i]);
+  if( i == 0xFF ){				// test parity
+    if( parity )
+      dcf77error = 1;
+    parity = 0;
+    return;
+  }
+  d = (u8 *)&newtime.minute + (i >> 4);		// byte address
+  i &= 0x0F;					// bit number
+  if( i == 0 )
+    *d = 0;					// clear all, if lsb
+  if( pulse )
+    *d += LPM(&BMASK[i]);			// set bit
+}
+
+
+void scan_dcf77( void )
+{
+  if( dcf77_pulse ){
+    if( dcf77_pulse > 3 && dcf77_pulse < 8 ){
+      decode_dcf77( 0 );
+    }else{
+      if( dcf77_pulse > 10 && dcf77_pulse < 14 ){
+	decode_dcf77( 1 );
+      }else{
+	dcf77error = 1;
+      }
+    }
+    dcf77_pulse = 0;
+  }
+
+  if( dcf77_period ){
+    if( newtime.second < 60 )
+      newtime.second++;
+    if( dcf77_period > 120 && dcf77_period < 140 ){
+      if( dcf77error == 0 && newtime.second == 59 ){
+        synchronize = 0xFF;
+	sync_sec();
+	time.second = 0;
+	time.minute = newtime.minute;
+	time.hour = newtime.hour;
+	time.wday = newtime.wday;
+	time.day = newtime.day;
+	time.month = newtime.month;
+	time.year = newtime.year;
+      }
+      newtime.second = 0;
+      dcf77error = 0;
+    }else{
+      if( dcf77_period < 60 || dcf77_period > 70 )
+        dcf77error = 1;
+    }
+    dcf77_period = 0;
+  }
+}
-- 
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