From df3441786186cc2155ba76b0e1d2a2bb035cc93e Mon Sep 17 00:00:00 2001
From: Theo Arends <11044339+arendst@users.noreply.github.com>
Date: Tue, 18 Feb 2020 18:10:36 +0100
Subject: [PATCH] Fix DS18x20 driver

---
 tasmota/xsns_05_ds18x20.ino | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/tasmota/xsns_05_ds18x20.ino b/tasmota/xsns_05_ds18x20.ino
index ba87e3a5d..5b46d5519 100644
--- a/tasmota/xsns_05_ds18x20.ino
+++ b/tasmota/xsns_05_ds18x20.ino
@@ -126,6 +126,8 @@ void OneWireWriteBit(uint8_t v)
   delayMicroseconds(delay_high[v]);
 }
 
+/*
+// Fails for reasons unknown to me
 uint8_t OneWireReadBit(void)
 {
   if (!ds18x20_dual_mode) {
@@ -143,6 +145,35 @@ uint8_t OneWireReadBit(void)
   delayMicroseconds(53);
   return r;
 }
+*/
+// Works fine in contrast to above. Why?
+void OneWireReadBit1(void)
+{
+  pinMode(ds18x20_pin, OUTPUT);
+  digitalWrite(ds18x20_pin, LOW);
+  delayMicroseconds(3);
+  pinMode(ds18x20_pin, Settings.flag3.ds18x20_internal_pullup ? INPUT_PULLUP : INPUT);  // SetOption74 - Enable internal pullup for single DS18x20 sensor
+}
+
+void OneWireReadBit2(void)
+{
+  digitalWrite(ds18x20_pin_out, LOW);
+  delayMicroseconds(3);
+  digitalWrite(ds18x20_pin_out, HIGH);
+}
+
+uint8_t OneWireReadBit(void)
+{
+  if (!ds18x20_dual_mode) {
+    OneWireReadBit1();
+  } else {
+    OneWireReadBit2();
+  }
+  delayMicroseconds(10);
+  uint8_t r = digitalRead(ds18x20_pin);
+  delayMicroseconds(53);
+  return r;
+}
 
 /*------------------------------------------------------------------------------------------*/
 
@@ -284,6 +315,7 @@ void Ds18x20Init(void)
   uint64_t ids[DS18X20_MAX_SENSORS];
 
   ds18x20_pin = pin[GPIO_DSB];
+
   if (pin[GPIO_DSB_OUT] < 99) {
     ds18x20_pin_out = pin[GPIO_DSB_OUT];
     ds18x20_dual_mode = true;    // Dual pins mode as used by Shelly
@@ -419,6 +451,8 @@ void Ds18x20Name(uint8_t sensor)
 
 void Ds18x20EverySecond(void)
 {
+  if (!ds18x20_sensors) { return; }
+
 #ifdef W1_PARASITE_POWER
   // skip access if there is still an eeprom write ongoing
   unsigned long now = millis();