122 lines
3.4 KiB
C++
122 lines
3.4 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(time_t t, uint8_t const *DCFpulse) {
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TickType_t startTime = xTaskGetTickCount();
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uint8_t sec = second(t);
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t = myTZ.toLocal(now());
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ESP_LOGD(TAG, "[%02d:%02d:%02d.%03d] DCF second %d", hour(t), minute(t),
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second(t), millisecond(), sec);
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// induce a DCF Pulse
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for (uint8_t pulse = 0; pulse <= 2; pulse++) {
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switch (pulse) {
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case 0: // start of second -> start of timeframe for logic signal
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if (DCFpulse[sec] != dcf_Z)
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digitalWrite(HAS_DCF77, dcf_low);
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break;
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case 1: // 100ms after start of second -> end of timeframe for logic 0
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if (DCFpulse[sec] == dcf_0)
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digitalWrite(HAS_DCF77, dcf_high);
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break;
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case 2: // 200ms after start of second -> end of timeframe for 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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// pulse pause
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vTaskDelayUntil(&startTime, pdMS_TO_TICKS(DCF77_PULSE_LENGTH));
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} // for
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} // DCF77_Pulse()
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uint8_t *IRAM_ATTR DCF77_Frame(time_t const tt) {
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// array of dcf pulses for one minute, secs 0..16 and 20 are never touched, so
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// we keep them statically to avoid same recalculation every minute
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static uint8_t DCFpulse[DCF77_FRAME_SIZE + 1] = {
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dcf_0, dcf_0, dcf_0, dcf_0, dcf_0, dcf_0, dcf_0,
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dcf_0, dcf_0, dcf_0, dcf_0, dcf_0, dcf_0, dcf_0,
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dcf_0, dcf_0, dcf_0, dcf_0, dcf_0, dcf_0, dcf_1};
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uint8_t Parity;
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time_t t = myTZ.toLocal(tt); // convert to local time
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// ENCODE DST CHANGE ANNOUNCEMENT (Sec 16)
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DCFpulse[16] = dcf_0; // not yet implemented
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// ENCODE DAYLIGHTSAVING (secs 17..18)
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DCFpulse[17] = myTZ.locIsDST(t) ? dcf_1 : dcf_0;
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DCFpulse[18] = myTZ.locIsDST(t) ? dcf_0 : dcf_1;
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// ENCODE MINUTE (secs 21..28)
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Parity = dec2bcd(minute(t), 21, 27, DCFpulse);
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DCFpulse[28] = setParityBit(Parity);
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// ENCODE HOUR (secs 29..35)
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Parity = dec2bcd(hour(t), 29, 34, DCFpulse);
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DCFpulse[35] = setParityBit(Parity);
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// ENCODE DATE (secs 36..58)
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Parity = dec2bcd(day(t), 36, 41, DCFpulse);
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Parity += dec2bcd((weekday(t) - 1) ? (weekday(t) - 1) : 7, 42, 44, DCFpulse);
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Parity += dec2bcd(month(t), 45, 49, DCFpulse);
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Parity += dec2bcd(year(t) - 2000, 50, 57, DCFpulse);
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DCFpulse[58] = setParityBit(Parity);
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// ENCODE MARK (sec 59)
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DCFpulse[59] = dcf_Z; // !! missing code here for leap second !!
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// timestamp this frame with it's minute
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DCFpulse[60] = minute(t);
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return DCFpulse;
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} // DCF77_Frame()
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// helper function to convert decimal to bcd digit
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uint8_t IRAM_ATTR dec2bcd(uint8_t const dec, uint8_t const startpos,
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uint8_t const endpos, uint8_t *DCFpulse) {
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uint8_t data = (dec < 10) ? dec : ((dec / 10) << 4) + (dec % 10);
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uint8_t parity = 0;
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for (uint8_t i = startpos; i <= endpos; i++) {
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DCFpulse[i] = (data & 1) ? dcf_1 : dcf_0;
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parity += (data & 1);
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data >>= 1;
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}
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return parity;
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}
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// helper function to encode parity
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uint8_t IRAM_ATTR setParityBit(uint8_t const p) {
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return ((p & 1) ? dcf_1 : dcf_0);
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}
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#endif // HAS_DCF77
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