101 lines
2.6 KiB
C++
101 lines
2.6 KiB
C++
/*
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// Emulate a DCF77 radio receiver to control an external clock
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//
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// a nice & free logic test program for DCF77 can be found here:
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https://www-user.tu-chemnitz.de/~heha/viewzip.cgi/hs/Funkuhr.zip/
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//
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// a DCF77 digital scope for Arduino boards can be found here:
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https://github.com/udoklein/dcf77
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//
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*/
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#ifdef HAS_DCF77
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#include "dcf77.h"
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// Local logging tag
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static const char TAG[] = __FILE__;
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// triggered by second timepulse to ticker out DCF signal
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void DCF77_Pulse(uint8_t bit) {
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TickType_t startTime;
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// induce a DCF Pulse
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for (uint8_t pulseLength = 0; pulseLength <= 2; pulseLength++) {
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startTime = xTaskGetTickCount(); // reference time pulse start
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switch (pulseLength) {
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case 0: // 0ms = start of pulse
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digitalWrite(HAS_DCF77, dcf_low);
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break;
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case 1: // 100ms = logic 0
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if (bit == 0)
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digitalWrite(HAS_DCF77, dcf_high);
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break;
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case 2: // 200ms = logic 1
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digitalWrite(HAS_DCF77, dcf_high);
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break;
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} // switch
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// delay to genrate pulseLength
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vTaskDelayUntil(&startTime, pdMS_TO_TICKS(100));
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} // for
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} // DCF77_Pulse()
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// helper function to convert decimal to bcd digit
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uint64_t dec2bcd(uint8_t const dec, uint8_t const startpos,
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uint8_t const endpos, uint8_t *parity) {
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uint8_t data = dec < 10 ? dec : ((dec / 10) << 4) + dec % 10;
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uint64_t bcd = 0;
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*parity = 0;
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for (uint8_t i = startpos; i <= endpos; i++) {
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bcd += data & 1 ? set_dcfbit(i) : 0;
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*parity ^= data & 1;
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data >>= 1;
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}
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return bcd;
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}
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// generates a 1 minute dcf pulse frame for calendar time t
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uint64_t DCF77_Frame(const struct tm t) {
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uint8_t parity = 0, parity_sum = 0;
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uint64_t frame = 0; // start with all bits 0
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// DST CHANGE ANNOUNCEMENT (16)
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// -- not implemented --
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// DAYLIGHTSAVING (17, 18)
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// "01" = MEZ / "10" = MESZ
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frame += t.tm_isdst > 0 ? set_dcfbit(17) : set_dcfbit(18);
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// LEAP SECOND (19)
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// -- not implemented --
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// BEGIN OF TIME INFORMATION (20)
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frame += set_dcfbit(20);
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// MINUTE (21..28)
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frame += dec2bcd(t.tm_min, 21, 27, &parity);
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frame += parity ? set_dcfbit(28) : 0;
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// HOUR (29..35)
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frame += dec2bcd(t.tm_hour, 29, 34, &parity);
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frame += parity ? set_dcfbit(35) : 0;
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// DATE (36..58)
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frame += dec2bcd(t.tm_mday, 36, 41, &parity);
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parity_sum ^= parity;
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frame += dec2bcd((t.tm_wday == 0) ? 7 : t.tm_wday, 42, 44, &parity);
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parity_sum ^= parity;
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frame += dec2bcd(t.tm_mon + 1, 45, 49, &parity);
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parity_sum ^= parity;
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frame += dec2bcd(t.tm_year + 1900 - 2000, 50, 57, &parity);
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parity_sum ^= parity;
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frame += parity_sum ? set_dcfbit(58) : 0;
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return frame;
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} // DCF77_Frame()
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#endif // HAS_DCF77
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