add tests, refine arduino program

.gitignore

@@ -5,3 +5,4 @@
 *.o
 decoder
 firmware
+tests

Makefile

@@ -3,7 +3,7 @@
 # SPDX-License-Identifier: GPL-3.0-only
 
 FIRMWARE = firmware/cwwvb.ino.elf
-all: decoder $(FIRMWARE)
+all: decoder $(FIRMWARE) run-tests
 
 decoder: decoder.cpp Makefile decoder.h
 	g++ -Wall -g -Og -o $@ $< -DMAIN
@@ -18,3 +18,14 @@ PORT := /dev/ttyACM0
 .PHONY: flash
 flash: $(FIRMWARE)
 	arduino-cli upload  -b adafruit:samd:adafruit_feather_m4 -i $(FIRMWARE:.elf=.hex) -p $(PORT)
+
+.PHONY: clean
+clean:
+	rm -f *.o decoder firmware
+
+.PHONY: run-tests
+run-tests: tests
+	./tests
+
+tests: decoder.cpp decoder.h Makefile tests.cpp
+	g++ -Wall -g -Og -o $@ $(filter %.cpp, $^)

cwwvb.ino

@@ -26,6 +26,8 @@ SAMDTimer ITimer0(TIMER_TC3);
 
 int cc;
 
+int tick_subsec;
+
 WWVBDecoder<> dec;
 constexpr int CENTRAL_COUNT = 3000000 / dec.SUBSEC;
 static_assert(CENTRAL_COUNT <= 65535);
@@ -75,7 +77,7 @@ void TimerHandler0(void) {
     digitalWrite(PIN_MON, LOW);
     TC3->COUNT16.CC[0].reg = cc;
 #if MONITOR_LL
-    putc(i ? '#' : '_');
+    putc(i ? '_' : '#', stderr);
 #endif
     if (introduced_error.load()) {
         introduced_error.fetch_sub(1);
@@ -84,7 +86,8 @@ void TimerHandler0(void) {
     if (dec.update(i)) {
         wq.put(try_decode);
     }
-    auto subsec = mod_diff<dec.SUBSEC>(dec.sos, dec.SUBSEC - 5);
+
+    auto subsec = mod_diff<dec.SUBSEC>(dec.subsec, tick_subsec);
     if (subsec == 0) {
         wq.put(tick);
     }
@@ -102,6 +105,8 @@ void set_tc(int n, bool hold) {
     if (n < -(int)CENTRAL_COUNT / 100)
         n = -(int)CENTRAL_COUNT / 100;
     cc = CENTRAL_COUNT + n;
+    moveto(1, 24);
+    fflush(stdout);
     fprintf(stderr, "Steer %+4d CC = %5d I = %+5d P=%+5d %.4s\n", n, cc, ss_I,
             ss_P, hold ? "HOLD" : "INTG");
 }
@@ -158,6 +163,7 @@ void loop() {
 
     digitalWrite(PIN_LED, HIGH);
     wq.take()();
+    fflush(stdout);
     digitalWrite(PIN_LED, LOW);
 }
 
@@ -223,7 +229,8 @@ void try_decode() {
     {
         char buf[snapshot.SYMBOLS];
         for (int i = 0; i < sizeof(buf); i++) {
-            buf[i] = '0' + snapshot.symbols.at(i);
+            static const char sym2char[] = "012?";
+            buf[i] = sym2char[snapshot.symbols.at(i)];
         }
         moveto(1, 25);
         printf("%.*s health=%3d%%", sizeof(buf), buf,
@@ -232,19 +239,19 @@ void try_decode() {
 
     if (snapshot.symbols.at(snapshot.SYMBOLS - 1) == 2) {
         if (snapshot.decode_minute(w)) {
+            tick_subsec = mod_diff<snapshot.SUBSEC>(snapshot.sos, 5);
             w.advance_minutes();
             ever_set = true;
+            display_time();
         }
     }
-
-    if (ever_set) {
-        tick();
-    }
 }
 
 void tick() {
+    // if (ever_set) {
     w.advance_seconds();
     display_time();
+    //}
 }
 
 extern "C" int write(int file, char *ptr, int len);

decoder.cpp

@@ -104,8 +104,12 @@ static bool last_yday(int year) { return 365 + isly(year); }
 
 // advance to exactly the top of the n'th minute from now
 void wwvb_time::advance_minutes(int n) {
-    if (seconds_in_minute() == 61) {
+    if (seconds_in_minute() != 60) {
         ls = 0;
+        if (dut1 < 0)
+            dut1 += 10;
+        else if (dut1 > 0)
+            dut1 -= 10;
     }
 
     second = 0;
@@ -122,7 +126,7 @@ void wwvb_time::advance_minutes(int n) {
     yday++;
     if (dst == 1)
         dst = 0;
-    if (dst == 2)
+    else if (dst == 2)
         dst = 3;
     if (yday < last_yday(year))
         return;
@@ -137,7 +141,7 @@ void wwvb_time::advance_minutes(int n) {
 using namespace std;
 
 int main() {
-    WWVBDecoder<120> dec;
+    WWVBDecoder<> dec;
 
     static char zone[] = "TZ=UTC";
     putenv(zone);

decoder.h

@@ -72,7 +72,7 @@ template <int N, int M> struct circular_symbol_array {
         return result;
     }
 
-    bool put(int v) {
+    int put(int v) {
         int result = 0;
         for (int j = 0; j < M; j++) {
             result = (result << 1) | data.put(v & (1 << (M - 1)));
@@ -89,7 +89,6 @@ struct wwvb_time {
     int16_t yday;
     int8_t year, hour, minute, second;
     int8_t ls, ly, dst, dut1;
-    int8_t month, mday;
 
     time_t to_utc() const;
     struct tm apply_zone_and_dst(int zone_offset, bool observe_dst) const;
@@ -234,11 +233,16 @@ struct WWVBDecoder {
         return expect ? count : length - count;
     }
 
-    // We're informed that a new second _just started_, so
+    // A second just concluded, so signal.at(BUFFER-1) is the last sample of
-    // signal.at(BUFFER-1) is the first sample of the new second. and
+    // the second, and signal.at(BUFFER-SUBSEC) is the first sample of the
-    // signal.at(BUFFER-SUBSEC-1) is the first sample of the previous second
+    // second
     void decode_symbol() {
-        constexpr auto OFFSET = BUFFER - SUBSEC - 1;
+        constexpr auto OFFSET = BUFFER - SUBSEC;
+#if 0
+        for(size_t i=0; i<SUBSEC; i++) {
+            printf("%c", signal.at(OFFSET + i) ? '_' : '#');
+        }
+#endif
         int count_a = count(OFFSET + p0, OFFSET + p1);
         int count_b = count(OFFSET + p1, OFFSET + p2);
         int count_c = count(OFFSET + p2, OFFSET + p3);
@@ -246,16 +250,23 @@ struct WWVBDecoder {
 
         int result = 0;
 
-        if (count_c > lc / 2)
+        if (count_c > lc / 2) {
-            result = 2;
+            if (count_b > lb / 2) {
-        else if (count_b > lb / 2)
+                result = 2;
+            } else {
+                result = 3; // a nonsense symbol
+            }
+        } else if (count_b > lb / 2) {
             result = 1;
+        }
 
         int h = 0;
-        h += check_health(count_a, la, 1);
+        if (result != 3) {
-        h += check_health(count_b, lb, result != 0);
+            h += check_health(count_a, la, 1);
-        h += check_health(count_c, lc, result == 2);
+            h += check_health(count_b, lb, result != 0);
-        h += check_health(count_d, ld, 0);
+            h += check_health(count_c, lc, result == 2);
+            h += check_health(count_d, ld, 0);
+        }
 
         int sc = symbol_count++;
         int si = sc % SYMBOLS;
@@ -264,6 +275,14 @@ struct WWVBDecoder {
         health += (h - oh);
 
         symbols.put(result);
+
+#if 0
+        printf(" %d\n", result);
+        for(size_t i=0; i<SYMBOLS; i++) {
+            printf("%d", symbols.at(i));
+        }
+        printf("\n", result);
+#endif
     }
 
     mutable bool bcderr;

tests.cpp

@@ -0,0 +1,124 @@
+// SPDX-FileCopyrightText: 2021 Jeff Epler
+//
+// SPDX-License-Identifier: GPL-3.0-only
+
+#ifndef ARDUINO
+
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include <doctest/doctest.h>
+
+#include "decoder.h"
+
+circular_bit_array<6> cba;
+circular_symbol_array<6, 4> csa;
+
+TEST_CASE("test bit array") {
+    for (int i = 0; i < 6; i++)
+        cba.put(0);
+
+    // The next puts need to read out six zeros
+    for (int i = 0; i < 6; i++)
+        CHECK(cba.put(1) == 0);
+
+    // The next puts need to read out six ones
+    for (int i = 0; i < 6; i++)
+        CHECK(cba.put(1) == 1);
+
+    cba.put(0);
+    // content now 111110
+
+    CHECK(cba.at(0) == 1);
+    CHECK(cba.at(1) == 1);
+    CHECK(cba.at(2) == 1);
+    CHECK(cba.at(3) == 1);
+    CHECK(cba.at(4) == 1);
+    CHECK(cba.at(5) == 0);
+}
+
+TEST_CASE("test symbol array") {
+    for (int i = 0; i < 6; i++)
+        csa.put(0);
+
+    // The next puts need to read out six zeros
+    for (int i = 0; i < 6; i++)
+        CHECK(csa.put(i) == 0);
+
+    // The next puts need to read out the values above
+    for (int i = 0; i < 6; i++)
+        CHECK(csa.put(1) == i);
+
+    csa.put(0);
+    csa.put(1);
+    csa.put(2);
+    csa.put(3);
+    csa.put(4);
+    csa.put(5);
+    // content now 012345
+
+    CHECK(csa.at(0) == 0);
+    CHECK(csa.at(1) == 1);
+    CHECK(csa.at(2) == 2);
+    CHECK(csa.at(3) == 3);
+    CHECK(csa.at(4) == 4);
+    CHECK(csa.at(5) == 5);
+}
+
+TEST_CASE("test leap second") {
+    struct wwvb_time ww = {
+        .yday = 366,
+        .year = 16,
+        .hour = 23,
+        .minute = 59,
+        .second = 59,
+        .ls = 1,
+        .ly = 1,
+        .dst = 0,
+        .dut1 = -4,
+    };
+
+    ww.advance_seconds();
+    CHECK(ww.second == 60);
+    CHECK(ww.ls);
+    CHECK(ww.dut1 == -4);
+
+    ww.advance_seconds();
+    CHECK(ww.second == 0);
+    CHECK(!ww.ls);
+    CHECK(ww.dut1 == 6);
+}
+
+TEST_CASE("test dst next day") {
+    struct wwvb_time ww = {
+        .yday = 73,
+        .year = 21,
+        .hour = 23,
+        .minute = 59,
+        .second = 59,
+        .ls = 1,
+        .ly = 1,
+        .dst = 2,
+    };
+
+    ww.advance_seconds();
+    CHECK(ww.second == 0);
+    CHECK(ww.dst == 3);
+}
+
+TEST_CASE("test std next day") {
+    struct wwvb_time ww = {
+        .yday = 311,
+        .year = 21,
+        .hour = 23,
+        .minute = 59,
+        .second = 59,
+        .ls = 1,
+        .ly = 1,
+        .dst = 1,
+    };
+
+    ww.advance_seconds();
+    CHECK(ww.second == 0);
+    CHECK(ww.dst == 0);
+}
+
+#endif