diff options
Diffstat (limited to 'dcf77.c')
| -rw-r--r-- | dcf77.c | 100 |
1 files changed, 100 insertions, 0 deletions
@@ -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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