From 94992f0597ed21d0c02ed38ebb5b9b5f25c3c40e Mon Sep 17 00:00:00 2001
From: Theo Arends <11044339+arendst@users.noreply.github.com>
Date: Sun, 27 Jun 2021 14:20:00 +0200
Subject: [PATCH] Revert changes DHT11 timing

---
 CHANGELOG.md            |  1 -
 RELEASENOTES.md         |  1 -
 tasmota/xsns_06_dht.ino | 28 ++++++++++++----------------
 3 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7956c25bb..9cc2fe944 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,7 +14,6 @@ All notable changes to this project will be documented in this file.
 - Speed up initial GUI console refresh
 - Simplified configuration for ir-full and removal of tasmota-ircustom
 - Add Esp32 Partition Manager as a Berry component
-- Update timing DHT11, AM2301 (DHT21, DHT22, AM2302, AM2321), SI7021 (#12488)
 
 ### Fixed
 - ESP32 Webcam add boundary marker before sending mjpeg image (#12376)
diff --git a/RELEASENOTES.md b/RELEASENOTES.md
index daab68a0f..8f90d9786 100644
--- a/RELEASENOTES.md
+++ b/RELEASENOTES.md
@@ -105,7 +105,6 @@ The latter links can be used for OTA upgrades too like ``OtaUrl http://ota.tasmo
 - Force ESP32 defines USE_UFILESYS, GUI_TRASH_FILE and #define GUI_EDIT_FILE
 - Speed up initial GUI console refresh
 - Simplified configuration for ir-full and removal of tasmota-ircustom [#12428](https://github.com/arendst/Tasmota/issues/12428)
-- Update timing DHT11, AM2301 (DHT21, DHT22, AM2302, AM2321), SI7021 [#12488](https://github.com/arendst/Tasmota/issues/12488)
 
 ### Fixed
 - DDS238-2 wrong reactive power value [#12283](https://github.com/arendst/Tasmota/issues/12283)
diff --git a/tasmota/xsns_06_dht.ino b/tasmota/xsns_06_dht.ino
index 46a250526..ffd6c4b44 100644
--- a/tasmota/xsns_06_dht.ino
+++ b/tasmota/xsns_06_dht.ino
@@ -25,9 +25,9 @@
  * Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  *
  * Changelog
- * 20210627 - https://github.com/arendst/Tasmota/pull/12488
  * 20210524 - https://github.com/arendst/Tasmota/issues/12180
  * 20200621 - https://github.com/arendst/Tasmota/pull/7468#issuecomment-647067015
+ * 20200313 - https://github.com/arendst/Tasmota/issues/7717#issuecomment-585833243
 \*********************************************************************************************/
 
 #define XSNS_06          6
@@ -50,20 +50,17 @@ struct DHTSTRUCT {
   float    h = NAN;
 } Dht[DHT_MAX_SENSORS];
 
-// 20210627: Changed from bool to uint32_t returning the time to wait until state changes
-uint32_t DhtWaitState(uint32_t sensor, uint32_t level) {
-  uint32_t startms = micros();
-  uint32_t timeout = startms + 100;
-
+bool DhtWaitState(uint32_t sensor, uint32_t level) {
+  unsigned long timeout = micros() + 100;
   while (digitalRead(Dht[sensor].pin) != level) {
     if (TimeReachedUsec(timeout)) {
       AddLog(LOG_LEVEL_DEBUG, PSTR(D_LOG_DHT D_TIMEOUT_WAITING_FOR " %s " D_PULSE),
         (level) ? D_START_SIGNAL_HIGH : D_START_SIGNAL_LOW);
-      return 0;                               // 20210627: Return 0 (==false for compatibility) if timeout reached
+      return false;
     }
     delayMicroseconds(1);
   }
-  return micros() - startms;
+  return true;
 }
 
 bool DhtRead(uint32_t sensor) {
@@ -82,8 +79,7 @@ bool DhtRead(uint32_t sensor) {
       break;
     case GPIO_DHT22:                                    // DHT21, DHT22, AM2301, AM2302, AM2321
 //      delay(2);   // minimum 1ms
-//      delayMicroseconds(2000);                          // 20200621: See https://github.com/arendst/Tasmota/pull/7468#issuecomment-647067015
-      delayMicroseconds(1100);                          // 20210627: Changed to Arduino DHT library value
+      delayMicroseconds(2000);                          // 20200621: See https://github.com/arendst/Tasmota/pull/7468#issuecomment-647067015
       break;
     case GPIO_SI7021:                                   // iTead SI7021
       delayMicroseconds(500);
@@ -108,14 +104,14 @@ bool DhtRead(uint32_t sensor) {
 
   uint32_t i = 0;
   noInterrupts();
-  if (DhtWaitState(sensor, 0)) {                        // Only wait for one state change to 0
+  if (DhtWaitState(sensor, 0) && DhtWaitState(sensor, 1) && DhtWaitState(sensor, 0)) {
     for (i = 0; i < 40; i++) {
       if (!DhtWaitState(sensor, 1)) { break; }
-      uint32_t wt = DhtWaitState(sensor, 0);            // Determine time to change state
-      if (0 == wt) { break; }
-      if (wt > 50) {
-        dht_data[i / 8] |= (1 << (7 - i % 8));          // If longer than 50 usec then 1, else 0
+      delayMicroseconds(32);                            // Was 30
+      if (digitalRead(Dht[sensor].pin)) {
+        dht_data[i / 8] |= (1 << (7 - i % 8));
       }
+      if (!DhtWaitState(sensor, 0)) { break; }
     }
   }
   interrupts();
@@ -134,7 +130,7 @@ bool DhtRead(uint32_t sensor) {
   switch (Dht[sensor].type) {
     case GPIO_DHT11:                                    // DHT11
       humidity = dht_data[0];
-      // DHT11 (Adafruit):
+      // 20200313: DHT11 (Adafruit):
       temperature = dht_data[2];
       if (dht_data[3] & 0x80) {
         temperature = -1 - temperature;