From b1c6d0e9f1a1bece8203a0bdd3e62fa720b022df Mon Sep 17 00:00:00 2001
From: dhineshkumarmcci <dhineshkumar@mcci.com>
Date: Fri, 10 Jul 2020 21:38:44 +0530
Subject: [PATCH] Fix #259: added code snippet to apply better Calibration
 value

---
 .../CatenaStm32L0_CalibrateSystemClock.cpp    | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/lib/stm32/stm32l0/CatenaStm32L0_CalibrateSystemClock.cpp b/src/lib/stm32/stm32l0/CatenaStm32L0_CalibrateSystemClock.cpp
index d8affa0..72341f7 100644
--- a/src/lib/stm32/stm32l0/CatenaStm32L0_CalibrateSystemClock.cpp
+++ b/src/lib/stm32/stm32l0/CatenaStm32L0_CalibrateSystemClock.cpp
@@ -253,6 +253,25 @@ uint32_t CatenaStm32L0::CalibrateSystemClock(void)
 		} while ((Calib != CalibNew) &&
 				(! fHaveSeenLow || !fHaveSeenHigh));
 
+	//
+	// Check which calibration value is better, 
+	// with lower error in PPM
+	//
+	if (fHaveSeenLow && fHaveSeenHigh)
+		{
+		uint32_t mSecondHighDiff;
+		uint32_t mSecondLowDiff;
+		
+		mSecondHighDiff = (mSecondHigh - 1000);
+		mSecondLowDiff = (1000 - mSecondLow);
+		
+		if (mSecondHighDiff > mSecondLowDiff)
+			fHaveSeenHigh = false;
+		
+		else if (mSecondHighDiff <= mSecondLowDiff)
+			fHaveSeenLow = false;
+		}
+
 	//
 	// We are going to take higher calibration value first and
 	// it allows us not to call LMIC_setClockError().