Diff: DHT11.cpp

Revision:

13:11d0770eb603

Parent:

12:af1eadec17e5

Child:

14:dc91e960af81

--- a/DHT11.cpp	Mon May 31 07:02:00 2021 +0000
+++ b/DHT11.cpp	Wed Sep 15 14:47:06 2021 +0000
@@ -1,4 +1,5 @@
 /* Copyright (c) 2014 Shigenori Inoue, MIT License
+ * Modified by Andy Pomfret 2021
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
  * and associated documentation files (the "Software"), to deal in the Software without restriction, 
@@ -25,7 +26,7 @@
     io_irq.fall(callback(this, &DHT11::neg_edge));
     io_irq.disable_irq();
     t.start();
-    first_time = true;
+    readNewData();
 }
 
 // Destructor
@@ -39,10 +40,10 @@
 int DHT11::readData(void)
 {
     // Checking the measurement frequency
-    if (chrono::duration_cast<chrono::milliseconds>(t.elapsed_time()).count() < 2000 && first_time == false) {
-        t.reset();
-        return READ_TOO_OFTEN;
-    }
+//    if (chrono::duration_cast<chrono::milliseconds>(t.elapsed_time()).count() < 2000) {
+//        t.reset();
+//        return READ_TOO_OFTEN;
+//    }
     
     // Initialize
     init();
@@ -57,8 +58,7 @@
     t.reset();
     io.output();
     io = 0;
-    do {
-    } while (chrono::duration_cast<chrono::milliseconds>(t.elapsed_time()).count() < 20 + t_tol_start);
+    thread_sleep_for(10 + t_tol_start);
     io.input();
     io = 1;
     
@@ -72,7 +72,7 @@
         }
     } while (io == 1);
 
-    // Wainting for the start of the ready signal
+    // Waiting for the start of the ready signal
     t.reset();
     do {
         if (t.elapsed_time().count() > 100) {
@@ -81,7 +81,7 @@
         }
     } while (io == 0);
 
-    // Wainting for the end of the ready signal
+    // Waiting for the end of the ready signal
     t.reset();
     do {
         if (t.elapsed_time().count() > 100) {
@@ -91,7 +91,7 @@
     } while (io == 1);
 
     // Starting the pulse width sensing
-    // by the use of interruptions
+    // by the use of interrupts
     io_irq.enable_irq();
 
     do {
@@ -104,30 +104,39 @@
     } while (eod == false);
 
     // Calculating the check sum
-    chksum = ((data & 0xff00000000) >> 32)
-             + ((data & 0x00ff000000) >> 24)
-             + ((data & 0x0000ff0000) >> 16)
-             + ((data & 0x000000ff00) >> 8);
+    chksum = (data >> 32)
+             + (data >> 24)
+             + (data >> 16)
+             + (data >> 8);
 
-    if (chksum != (data & 0x00000000ff)) {
+    if ((chksum & 0xff) != (data & 0x00000000ff)) {
         t.reset();
         return CHKSUM_ERR;
     } else {
         t.reset();
-        first_time = false;
         return OK;
     }
 }
 
+void DHT11::readNewData(void) {
+    do; while (readData() != OK);
+}
+
 // Extracting humidity data from the received data
 int DHT11::readHumidity(void)
 {
+    if (t.elapsed_time() >= 2000ms) {
+        readNewData();
+    }
     return (data & 0xff00000000) >> 32;
 }
 
 // Extracting temperature data from the received data
 int DHT11::readTemperature(void)
 {
+    if (t.elapsed_time() >= 2000ms) {
+        readNewData();
+    }
     return (data & 0x0000ff0000) >> 16;
 }
 
@@ -145,19 +154,19 @@
 
 void DHT11::pos_edge(void)
 {
-    // Disabling the interruptions
+    // Disabling the interrupts
     io_irq.disable_irq();
 
     // Initializing the Timer
     t.reset();
 
-    // Enabling the interruptions
+    // Enabling the interrupts
     io_irq.enable_irq();
 }
 
 void DHT11::neg_edge(void)
 {
-    // Disabling the interruptions
+    // Disabling the interrupts
     io_irq.disable_irq();
 
     // Reading the positive pulse width