Diff: main.cpp

Revision:

61:00601fb0a3b9

Parent:

60:6ae1a2390600

Child:

62:9e5cb78d25e4

--- a/main.cpp	Sat Sep 08 21:37:35 2018 -0700
+++ b/main.cpp	Sun Sep 09 06:03:33 2018 -0700
@@ -49,6 +49,12 @@
 I2C     i2c(D4, D5);             // I2C port
 Ticker  SecTenth_Beat;           // .1 second ticker
 Ticker  Sec_Beat;                // 1 second ticker
+
+
+int begin;
+int end;
+double secCorrection;
+
 Serial  PC(USBTX, USBRX);        // Virtual COM via USB (PC connection)
 Serial  GPS(D1, D0);             // Serial port for GPS module
 
@@ -56,11 +62,15 @@
 time_t      seconds;       // Real-Time Clock (RTC) timestamp
 unsigned int value = 0;    // displayed value on the 6-digits of the display
 
-uint32_t    Count1, Count2;    // pulse counters (32-bit)
+uint32_t Count1, Count2;    // pulse counters (32-bit)
+uint32_t Count1Save;
+uint32_t Count2Save;
+
 int32_t     TickerCorrection = 0;
 uint32_t    TickerPeriod = 100000;
 uint32_t    TickerPeriodCount = 0;
 const uint32_t TickerPeriodsPerSecond = 1000000/TickerPeriod;
+const uint32_t TickerTicksPerSecond   = TickerPeriod*TickerPeriodsPerSecond;
 const int16_t TickerCorrectionMax = 99;
 const int16_t TickerCorrectionMin = -99;
 
@@ -102,7 +112,7 @@
    DigitsDisplay.Display_6D_write(0x543210);
    DigitsDisplay.Display_2D_write(0);
 
-   // RTC is supposed to be loose time at power down (no backup battery)
+   // RTC is supposed to lose time at power down (no backup battery)
    // An initialization is performed anyway 
    set_time(0); // Set time
     
@@ -117,6 +127,8 @@
    SecTenth_Beat.attach_us(&UpdateIO,  TickerPeriod);
    //RTC::attach(&Update, RTC::Second);
    //RTC::detach(RTC::Second);  
+   time.start();
+   begin = timer.read_us();
   
    TRIG1.rise(&Count1_up);     
    TRIG2.rise(&Count2_up);         
@@ -151,7 +163,21 @@
 {
    if (++TickerPeriodCount >= TickerPeriodsPerSecond)
    {
+      // Capture the counts early so they will be more accurate
+      Count1Save = Count1;
+      Count2Save = Count2;
+      Count1 = 0;
+      Count2 = 0;
+
+      // Correct for ticker inaccuracy
+      end = timer.read_us();
+      int diff = end - begin;
+      secCorrection = diff/TickerTicksPerSecond;
+      Count1Save = Count1Save/secCorrection;
+      Count2Save = Count2Save/secCorrection;
+      
       TickerPeriodCount = 0;
+
       UpdateOutput();
    }
    UpdateInput();
@@ -159,12 +185,6 @@
 
 void UpdateOutput()
 {
-   // Capture the counts early so they will be more accurate
-   uint32_t Count1Save = Count1;
-   uint32_t Count2Save = Count2;
-   Count1 = 0;
-   Count2 = 0;
-
    if(Stopped)
    {    
       // disable interrupts on TRIG1 and TRIG2