From 888d8b312a4913516af0857067da567111af3b0e Mon Sep 17 00:00:00 2001
From: Phil Howard <phil@gadgetoid.com>
Date: Fri, 1 Dec 2017 14:08:40 +0000
Subject: [PATCH] Convert negative gas resistance readings to unsigned int32

---
 library/bme680/__init__.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/library/bme680/__init__.py b/library/bme680/__init__.py
index 1e5bfcb..a8f7720 100644
--- a/library/bme680/__init__.py
+++ b/library/bme680/__init__.py
@@ -354,6 +354,9 @@ class BME680(BME680Data):
         var3 = ((lookupTable2[gas_range] * var1) >> 9)
         calc_gas_res = ((var3 + (var2 >> 1)) / var2)
 
+        if calc_gas_res < 0:
+            calc_gas_res = (1<<32) + calc_gas_res
+
         return calc_gas_res
 
     def _calc_heater_resistance(self, temperature):