From ddb3d391f9e5001624e4b38aae448ef8d812d741 Mon Sep 17 00:00:00 2001
From: Peter Hinch <peter@hinch.me.uk>
Date: Wed, 6 Jan 2016 12:07:08 +0000
Subject: [PATCH] Clear existing cal at start of getcal()

---
 DS3231/ds3231_pb.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/DS3231/ds3231_pb.py b/DS3231/ds3231_pb.py
index a039750..f03d3cc 100644
--- a/DS3231/ds3231_pb.py
+++ b/DS3231/ds3231_pb.py
@@ -99,6 +99,7 @@ class DS3231:
 # to store the calibration factor on disk and issue rtc.calibration(factor) on boot.
 
     def getcal(self, seconds):
+        rtc.calibration(0)                      # Clear existing cal
         self.save_time()                        # Set DS3231 from RTC
         self.await_transition()
         rtcstart = now()