kopia lustrzana https://github.com/roncarr880/QRP_LABS_WSPR
Experiment with wwvb receiver
roncarr880
GitHub
rodzic
aaa8b70631
commit
30b915a045
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@ -0,0 +1,325 @@
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/*
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* WWVB experiments
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*
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*/
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#include <LCD5110_Basic.h>
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LCD5110 LCD( 2,3,4,6,5 );
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extern uint8_t SmallFont[];
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extern uint8_t MediumNumbers[];
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extern uint8_t BigNumbers[];
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#define WWVB_IN 7
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#define PPS_OUT 8
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long tm_correct_count = 60000; // add or sub one ms for time correction per this many ms
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int8_t tm_correction = 1; // 0, 1 or -1 time correction
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long time_adjust;
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int gmon = 1,gday = 1,gyr = 1,ghr,gmin;
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int tot_days = 1;
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uint16_t leap = 1;
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uint64_t wwvb_data, wwvb_sync, wwvb_errors;
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uint8_t DST; // daylight savings bit
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void setup() {
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pinMode(WWVB_IN, INPUT_PULLUP); // sample wwvb receiver signal
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pinMode(PPS_OUT, OUTPUT);
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Serial.begin(9600);
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LCD.InitLCD();
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LCD.setFont(SmallFont);
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LCD.print("WWVB PPS TEST",CENTER,8*0);
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delay( 5000 );
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LCD.clrRow(0);
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}
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void loop() {
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static unsigned long tm;
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if( tm != millis() ){
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tm = millis();
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wwvb_sample2(tm);
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}
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}
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void calc_date(){ // from total days and leap flag
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const int cal[2][12] =
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{ 31,28,31,30,31,30,31,31,30,31,30,31,
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31,29,31,30,31,30,31,31,30,31,30,31 };
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int i,d;
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d = tot_days;
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for( i = 0; i < 12; ++i ){
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if( d <= cal[leap][i] ) break;
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d -= cal[leap][i];
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}
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gmon = i + 1;
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gday = d;
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}
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// WWVB receiver in a fringe area - integrate the signal to remove noise
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// Although it probably makes more sense to dump the integrator 10 times per second, here we use 8.
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// sample each millisecond, sum 100 or 150 samples , decide if low or high, shift into temp variable
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// at end of 1 second( 8 bits), decide if temp has a 1, 0, or sync. Shift into 64 bit data and sync variables.
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// when the sync variable contains the magic number, decode the 64 bit data.
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// each second starts with a low signal and ends with a high signal
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// much like software sampling rs232 start and stop bits.
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// this routine runs fast by design until it locks on the wwvb signal( or slow depending upon point of view )
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void wwvb_sample2(unsigned long t){
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static unsigned long old_t;
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int loops;
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uint8_t b,s,e;
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static uint8_t wwvb_clk, wwvb_sum, wwvb_tmp, wwvb_count; // data decoding
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const uint8_t counts[8] = { 100,100,150,150,150,150,100,100 }; // total of 1000 ms
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static uint8_t secs,errors,early,late;
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static uint8_t dither = 4; // quick sync, adjusts to 1 when signal is good
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static uint8_t enable_dither; // enabled when think have a good wwvb signal
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char ch[2];
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//static char valp[9]; // LCD display of slow/fast timekeeping
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//static int8_t vali, valc;
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loops = t - old_t;
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old_t = t;
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if( loops > 10 ) loops = 1; // startup
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while( loops-- ){ // repeat for any missed milliseconds
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// adjust for 16mhz millis() error
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if( ++time_adjust >= tm_correct_count && wwvb_clk != 0 ){
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time_adjust = 0;
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wwvb_clk += tm_correction;
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}
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if( digitalRead(WWVB_IN) == LOW ) ++wwvb_sum;
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if( --wwvb_clk == 0 ){ // end of period, dump integrator
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if( wwvb_sum == counts[wwvb_count] ) enable_dither = 1; // good signal detect, allow slip in time
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b = ( wwvb_sum > (counts[wwvb_count] >> 1) ) ? 0 : 128;
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wwvb_tmp >>= 1;
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wwvb_tmp |= b;
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wwvb_sum = 0;
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// 8 dumps of the integrator is one second, decode this bit
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wwvb_count++;
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wwvb_count &= 7;
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if( wwvb_count == 0 ) digitalWrite( PPS_OUT,HIGH);
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if( wwvb_count == 1 ) digitalWrite( PPS_OUT,LOW);
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wwvb_clk = counts[wwvb_count]; // 100 100 150 150 150 150 100 100
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// decode 0 1 sync stop should be high
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if( wwvb_count == 0 ){ // decode time
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// clocks late or early, just dither them back and forth across the falling edge
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// when not in sync, more 1's than 0's are detected and this slips in time.
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if( wwvb_tmp != 0xff && wwvb_tmp != 0x00 ){
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if( digitalRead(WWVB_IN) == 0 ){
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++late; // sampling late
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wwvb_clk -= enable_dither * dither; // adjust sample to earlier
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}
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else{
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++early; // need to sample later
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wwvb_clk += enable_dither * dither; // longer clock
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}
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}
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// decode
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// 11111100 is a zero, 11110000 is a one, 11000000 is a sync
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b = 0; s = 0; e = 1; // assume it is an error
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pbin( wwvb_tmp );
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// strict decode works well, use loose decode for common bit errors ?
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if( wwvb_tmp == 0xfc || wwvb_tmp == 0xfd ) e = 0, b = 0;
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if( wwvb_tmp == 0xf0 ) e = 0, b = 1;
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if( wwvb_tmp == 0xc0 ) e = 0, s = 1;
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ch[0] = 'e'; ch[1] = 0;
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if( e == 0 ){
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if( s == 1 ) ch[0] = 'S';
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else if( b == 1 ) ch[0] = '1';
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else ch[0] = '0';
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}
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LCD.print(ch,LEFT,0);
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if( e ) ++errors;
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wwvb_data <<= 1; wwvb_data |= b; // shift 64 bits data
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wwvb_sync <<= 1; wwvb_sync |= s; // sync
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wwvb_errors <<= 1; wwvb_errors |= e; // errors
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// magic 64 bits of sync ( looking at 60 seconds of data with 4 seconds of the past minute )
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// xxxx1000000001 0000000001 0000000001 0000000001 0000000001 0000000001
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// wwvb_sync &= 0x0fffffffffffffff; // mask off the old bits from previous minute
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// instead of masking, use the old bits to see the double sync bits at 0 of this minute
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// and 59 seconds of the previous minute. This decodes at zero time.
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if( wwvb_sync == 0b0001100000000100000000010000000001000000000100000000010000000001 ){
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if( wwvb_errors == 0 ){ // decode if no bit errors
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wwvb_decode();
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secs = 59; // secs = 0 next statement
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}
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}
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Serial.print( secs ); Serial.write(' ');
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if( secs == 29 || secs == 59 ) Serial.println();
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LCD.setFont(MediumNumbers);
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LCD.printNumI(secs,RIGHT,2*8,2,'0');
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LCD.setFont(SmallFont);
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if( ++secs >= 60 ){ // adjust dither each minute
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dither = ( errors >> 4 ) + 1;
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// will this work for both slow and fast 16 mhz clock?
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if( errors < 32 ){
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//tm_correct_count += tm_correction * (late - early); // ? which is correct ?
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tm_correct_count += tm_correction * (early - late);
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if( tm_correct_count > 120000 ){
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tm_correct_count = 119000;
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tm_correction *= -1;
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}
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}
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Serial.print( errors ); Serial.write(' ');
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Serial.print( tm_correction); Serial.write(' ');
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Serial.println( tm_correct_count );
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LCD.printNumI( tm_correct_count,LEFT,1*8,6,' ');
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LCD.printNumI( tm_correction,8*6,1*8,2,' ');
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LCD.printNumI(errors,RIGHT,1*8,2,' ');
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enable_dither = early = late = secs = errors = 0; // reset the stats for the next minute
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if( wwvb_errors > 0 ) keep_time();
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}
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} // end decode time
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} // end integration timer
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} // loops - repeat for lost milliseconds if any
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}
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void wwvb_decode(){ // WWVB transmits the data for the previous minute just ended
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uint16_t tmp;
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uint16_t tmp2;
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uint16_t yr;
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uint16_t hr;
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uint16_t mn;
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uint16_t dy;
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uint8_t i;
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//tmp2 = frame_sec;
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//tmp = frame_msec; // capture milliseconds value before it is corrected so we can print it.
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//++decodes;
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yr = wwvb_decode2( 53, 0x1ff ); // year is 0 to 99
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dy = wwvb_decode2( 33, 0xfff ); // day is 0 to 365/366
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hr = wwvb_decode2( 18, 0x7f );
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mn = wwvb_decode2( 8, 0xff );
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leap = wwvb_decode2( 55, 0x1 );
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DST = wwvb_decode2( 57, 0x1 ); // in effect bit ( using bit 58 gave wrong time for one day )
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/***
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if( ( mn & 1 ) == 0 ){ //last minute was even so just hit the 60 second mark in the frame
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// only apply clock corrections in the middle of the two minute frame or may
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// otherwise mess up the frame timing
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if( frame_sec == 59 && frame_msec >= 500 ) ; // ok
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else if( frame_sec == 60 && frame_msec < 500 ) ; // ok
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else{ // way off, reset to the correct time
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frame_sec = 60;
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frame_msec = 0;
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// FF = 0, ff = 0; // reset timing fudge factor
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// clr_trends = 1; // the trend buckets will be incorrect now
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}
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}
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****/
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ghr = hr;
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gmin = mn;
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gyr = yr;
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tot_days = dy;
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calc_date();
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keep_time(); // wwvb sends minute just ended info, so increment
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//calc_date( );
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//time_flags |= TS;
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}
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// wwvb fields all decode about the same way
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uint16_t wwvb_decode2( uint8_t pos, uint16_t mask ){
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uint16_t tmp;
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uint16_t val;
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tmp = ( wwvb_data >> ( 59 - pos ) ) & mask;
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val = 0;
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if( tmp & 0x800 ) val += 200;
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if( tmp & 0x400 ) val += 100;
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if( tmp & 0x100 ) val += 80;
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if( tmp & 0x80 ) val += 40;
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if( tmp & 0x40 ) val += 20;
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if( tmp & 0x20 ) val += 10;
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val += (tmp & 0xf);
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return val;
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}
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void keep_time(){
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if( ++gmin >= 60 ){
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gmin = 0;
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if( ++ghr >= 24 ){
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ghr = 0;
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++tot_days;
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if( tot_days > 365 + leap ) ++gyr, tot_days = 1;
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calc_date();
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}
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}
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p_fill( gmon,2 ); Serial.write('/');
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p_fill( gday,2 ); Serial.write('/');
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Serial.print("20"); p_fill(gyr,2); Serial.write(' '); Serial.write(' ');
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p_fill( ghr,2); Serial.write(':');
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p_fill( gmin,2 );
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Serial.println();
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LCD.setFont(MediumNumbers);
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LCD.printNumI(ghr,LEFT,2*8,2,'0');
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LCD.printNumI(gmin,CENTER,2*8,2,'0');
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LCD.setFont(SmallFont);
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LCD.printNumI(gmon,0,5*8,2,'0');
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LCD.print("/",3*6,5*8);
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LCD.printNumI(gday,5*6,5*8,2,'0');
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LCD.print("/",8*6,5*8);
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LCD.printNumI(gyr,10*6,5*8,2,'0');
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}
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void p_fill( int val, int digits ){ // zero fill printing
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if( digits >= 4 && val < 1000 ) Serial.write('0');
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if( digits >= 3 && val < 100 ) Serial.write('0');
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if( digits >= 2 && val < 10 ) Serial.write('0');
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Serial.print(val);
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}
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void pbin( uint8_t val ){
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int i;
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uint8_t v;
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for( i = 7; i >=0; --i ){
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v = 0;
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if( val & _BV(i)) v = 1;
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LCD.printNumI( v, 78-6*i, 0*8);
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}
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}
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