Switch to using micros() insteam of ESP.getCycleCount()
This commit is contained in:
Chris Liebman
parent
9c65ef10e9
commit
be663b01d8
209
ESPNTPServer.cpp
209
ESPNTPServer.cpp
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@ -21,20 +21,33 @@
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*/
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#include "ESPNTPServer.h"
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#include <lwip/def.h> // htonl() & ntohl()
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#define DEBUG
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#include "Logger.h"
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#include <lwip/def.h> // htonl() & ntohl()
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//define NTP_PACKET_DEBUG
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int8_t precision;
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volatile uint32_t dispersion;
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volatile uint32_t seconds;
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volatile uint32_t cycles;
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volatile uint32_t last_cpu_cycles;
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volatile uint32_t min_cycles;
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volatile uint32_t max_cycles;
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volatile uint32_t last_micros;
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volatile uint32_t micros_wraps;
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volatile uint32_t min_micros;
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volatile uint32_t max_micros;
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#if defined(MICROS_HISTORY_SIZE)
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volatile uint32_t micros_history[MICROS_HISTORY_SIZE];
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volatile uint16_t micros_history_count;
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volatile uint16_t micros_history_index;
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#endif
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AsyncUDP udp;
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DS3231 rtc; // real time clock on i2c interface
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#ifdef DEBUG
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#ifdef NTP_PACKET_DEBUG
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void dumpNTPPacket(NTPPacket* ntp)
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{
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dbprintf("size: %u\n", sizeof(*ntp));
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@ -59,30 +72,51 @@ void dumpNTPPacket(NTPPacket* ntp)
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void oneSecondInterrupt()
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{
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uint32_t cpu_cycles = ESP.getCycleCount();
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uint32_t cur_micros = micros();
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//
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// the first time around we just initialize the last value
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//
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if (last_cpu_cycles == 0)
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if (last_micros == 0)
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{
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last_cpu_cycles = cpu_cycles;
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last_micros = cur_micros;
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return;
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}
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cycles = cpu_cycles - last_cpu_cycles;
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last_cpu_cycles = cpu_cycles;
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if (cur_micros < last_micros)
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{
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++micros_wraps;
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}
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uint32_t micros_count = cur_micros - last_micros;
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last_micros = cur_micros;
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if (min_micros == 0 || micros_count < min_micros)
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{
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min_micros = micros_count;
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}
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if (micros_count > max_micros)
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{
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max_micros = micros_count;
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}
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#if defined(MICROS_HISTORY_SIZE)
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micros_history[micros_history_index++] = micros_count;
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if (micros_history_index >= MICROS_HISTORY_SIZE)
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{
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micros_history_index = 0;
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}
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if (micros_history_count < MICROS_HISTORY_SIZE)
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{
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micros_history_count++;
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}
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#endif
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//
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// increment seconds
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//
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seconds += 1;
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if (min_cycles == 0 || cycles < min_cycles)
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{
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min_cycles = cycles;
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}
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if (cycles > max_cycles)
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{
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max_cycles = cycles;
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}
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#if defined(DEBUG)
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digitalWrite(LED_PIN, digitalRead(LED_PIN) ? LOW : HIGH);
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#endif
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@ -103,24 +137,61 @@ void waitForEdge(int edge)
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void getNTPTime(NTPTime *time)
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{
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time->seconds = toNTP(seconds);
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uint32_t cpu_cycles = ESP.getCycleCount();
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uint32_t cycles_delta = cpu_cycles - last_cpu_cycles;
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uint32_t cur_micros = micros();
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uint32_t micros_delta = cur_micros - last_micros;
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//
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// if cycles_delta is at or bigger than cycles then
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// if micros_delta is at or bigger than one second then
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// use the max fraction.
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//
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if (cycles_delta >= cycles)
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if (micros_delta >= 1000000)
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{
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time->fraction = 0xffffffff;
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return;
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}
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double percent = (double)cycles_delta / (double)cycles;
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//dbprintf("cycles_delta: %lu cycles: %lu percent: %lf\n", cycles_delta, cycles, percent);
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double percent = us2s(micros_delta);
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//dbprintf("micros_delta: %lu percent: %lf\n", micros_delta, percent);
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time->fraction = (uint32_t)(percent * (double)4294967296L);
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}
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int8_t computePrecision()
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{
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NTPTime t;
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unsigned long start = micros();
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for (int i = 0; i < PRECISION_COUNT; ++i)
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{
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getNTPTime(&t);
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}
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unsigned long end = micros();
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double total = (double)(end - start) / 1000000.0;
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double time = total / PRECISION_COUNT;
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double prec = log2(time);
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dbprintf("computePrecision: total:%f time:%f prec:%f\n", total, time, prec);
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return (int8_t)prec;
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}
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int updateSeconds()
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{
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DS3231DateTime dt;
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if (rtc.readTime(dt))
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{
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dbprintln("updateSeconds: FAILED to read RTC, clearing bus & not checking seconds!");
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WireUtils.clearBus();
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return -1;
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}
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uint32_t old_seconds = seconds;
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uint32_t now = dt.getUnixTime();
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if (now != seconds)
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{
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seconds = now;
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dbprintf("updateSeconds: updated seconds from %lu to %lu\n", old_seconds, now);
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}
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return 0;
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}
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void recievePacket(AsyncUDPPacket aup)
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{
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NTPTime recv_time;
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@ -150,8 +221,10 @@ void recievePacket(AsyncUDPPacket aup)
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//
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ntp.flags = setLI(LI_NONE) | setVERS(NTP_VERSION) | setMODE(MODE_SERVER);
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ntp.stratum = 1;
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ntp.precision = -18;
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// TODO: root delay, and root dispersion
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ntp.precision = precision;
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// TODO: compute actual root delay, and root dispersion
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ntp.delay = (uint32)(0.000001 * 65536);
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ntp.dispersion = dispersion;
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strncpy((char*)ntp.ref_id, REF_ID, sizeof(ntp.ref_id));
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ntp.orig_time = ntp.xmit_time;
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ntp.recv_time = recv_time;
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@ -174,21 +247,24 @@ void recievePacket(AsyncUDPPacket aup)
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void setup()
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{
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dbbegin(115200);
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dbprintln("");
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dbprintln("Startup!");
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dbprintln("\n\nStartup!");
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pinMode(SYNC_PIN, INPUT);
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pinMode(LED_PIN, OUTPUT);
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seconds = 0;
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cycles = 0;
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max_cycles = 0;
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min_cycles = 0;
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last_cpu_cycles = 0;
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max_micros = 0;
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min_micros = 0;
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last_micros = 0;
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#if defined(MICROS_HISTORY_SIZE)
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micros_history_count = 0;
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micros_history_index = 0;
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#endif
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attachInterrupt(SYNC_PIN, &oneSecondInterrupt, FALLING);
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dbprintf("delay 2 seconds to make sure we have a clean cycle count\n");
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delay(2000);
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WiFiManager wifi;
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//wifi.setDebugOutput(false);
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String ssid = "SynchroClock" + String(ESP.getChipId());
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wifi.autoConnect(ssid.c_str(), NULL);
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Wire.begin();
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Wire.setClockStretchLimit(1500);
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@ -204,6 +280,13 @@ void setup()
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delay(1000);
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}
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attachInterrupt(SYNC_PIN, &oneSecondInterrupt, FALLING);
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dbprintf("delay %d seconds to make sure we have a clean last_micros value\n", WARMUP_SECONDS);
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delay(WARMUP_SECONDS*1000);
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precision = computePrecision();
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#if 0
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waitForEdge(SYNC_EDGE_FALLING);
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delay(2); // for some reason we get errors if we read too soon after the falling edge.
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DS3231DateTime dt;
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@ -218,11 +301,7 @@ void setup()
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delay(1000);
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}
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seconds = dt.getUnixTime();
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WiFiManager wifi;
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//wifi.setDebugOutput(false);
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String ssid = "SynchroClock" + String(ESP.getChipId());
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wifi.autoConnect(ssid.c_str(), NULL);
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#endif
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//
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// initialize UDP handler
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@ -237,7 +316,6 @@ void setup()
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}
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void loop()
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{
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static int last_sync_level;
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@ -248,32 +326,33 @@ void loop()
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int sync_level = digitalRead(SYNC_PIN);
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if (sync_level == 0 && sync_level != last_sync_level)
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{
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DS3231DateTime dt;
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delay(2); // for some reason we get errors if we read too soon after the falling edge.
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if (rtc.readTime(dt))
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{
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dbprintln("loop: FAILED to read RTC, clearing bus & not checking seconds!");
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WireUtils.clearBus();
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}
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else
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{
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uint32_t old_seconds = seconds;
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uint32_t now = dt.getUnixTime();
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if (now != seconds)
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{
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seconds = now;
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dbprintf("loop: updated seconds from %lu to %lu\n", old_seconds, now);
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}
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}
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delay(2); // for some reason I get errors if we read too soon after the falling edge.
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updateSeconds();
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}
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last_sync_level = sync_level;
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#if 1
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static uint32_t last_seconds;
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if (seconds != last_seconds && (seconds % 300) == 0)
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if (seconds != last_seconds && (seconds % 60) == 0)
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{
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dbprintf("min_cycles:%lu max_cycles:%lu cycles:%lu\n", min_cycles, max_cycles, cycles);
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#if defined(MICROS_HISTORY_SIZE)
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double mean = 0.0;
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for (int i = 0; i < micros_history_count; ++i)
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{
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mean += us2s(micros_history[i]);
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}
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mean = mean / micros_history_count;
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double stdev = 0.0;
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for (int i = 0; i < micros_history_count; ++i)
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{
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stdev += pow(us2s(micros_history[i]) - mean, 2);
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}
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stdev = sqrt(stdev / micros_history_count);
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dbprintf("mean:%f stdev:%f ", mean, stdev);
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#endif
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double disp = us2s(max(abs(1000000-max_micros), abs(1000000-min_micros)));
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dbprintf("min:%f max:%f jitter:%f dispersion:%f\n", us2s(min_micros), us2s(max_micros), us2s(max_micros-min_micros), disp);
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dispersion = (uint32_t)(disp * 65536.0);
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}
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last_seconds = seconds;
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#endif
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}
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@ -39,6 +39,12 @@
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#define SYNC_EDGE_RISING 1
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#define SYNC_EDGE_FALLING 0
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#define WARMUP_SECONDS 2
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#define MICROS_HISTORY_SIZE 1000
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#define PRECISION_COUNT 10000
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#define us2s(x) (((double)x)/1000000.0) // microseconds to seconds
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typedef struct ntp_time
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{
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uint32_t seconds;
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@ -76,7 +82,7 @@ typedef struct ntp_packet
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#define NTP_VERSION 4
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#define REF_ID "PPS" // "GPS" when we have one!
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#define REF_ID "PPS " // "GPS " when we have one!
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#define setLI(value) ((value&0x03)<<6)
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#define setVERS(value) ((value&0x07)<<3)
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@ -90,4 +96,8 @@ typedef struct ntp_packet
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#define toEPOCH(t) ((uint32_t)t-SEVENTY_YEARS)
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#define toNTP(t) ((uint32_t)t+SEVENTY_YEARS)
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// simple versions - we don't worry about side effects
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#define max(a, b) ((a) < (b) ? (b) : (a))
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#define min(a, b) ((a) < (b) ? (a) : (b))
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#endif /* _ESPNTPServer_H_ */
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