fix: add timeout handling to potentially infinite loop (#78)

devmirek · web-flow · commit bff9430086b5 · 2024-07-03T09:37:42.000+02:00
diff --git a/ADS1X15.cpp b/ADS1X15.cpp
@@ -451,7 +451,12 @@ int16_t ADS1X15::_readADC(uint16_t readmode)
   _requestADC(readmode);
   if (_mode == ADS1X15_MODE_SINGLE)
   {
-    while ( isBusy() ) yield();   //  wait for conversion; yield for ESP.
+    unsigned long start = millis();
+    while (isBusy()) {
+      yield();   //  wait for conversion; yield for ESP.
+      if ((start + ADS1X15_READ_TIMEOUT_MS) < millis())
+        return ADS1X15_ERROR_TIMEOUT;
+    }
   }
   else
   {
@@ -737,4 +742,3 @@ void ADS1115::requestADC_Differential_2_3()
 
 
 //  -- END OF FILE --
-
diff --git a/ADS1X15.h b/ADS1X15.h
@@ -24,9 +24,13 @@
 #define ADS1115_ADDRESS                   0x48
 #endif
 
+#ifndef ADS1X15_READ_TIMEOUT_MS
+#define ADS1X15_READ_TIMEOUT_MS           200 //Longest acquisition time is 125ms (8SPS)
+#endif
 
 #define ADS1X15_OK                        0
 #define ADS1X15_INVALID_VOLTAGE           -100
+#define ADS1X15_ERROR_TIMEOUT             -101
 #define ADS1X15_INVALID_GAIN              0xFF
 #define ADS1X15_INVALID_MODE              0xFE
 
@@ -268,4 +272,3 @@ class ADS1115 : public ADS1X15
 
 
 //  -- END OF FILE --
-

Original file line number	Diff line number	Diff line change
`@@ -451,7 +451,12 @@ int16_t ADS1X15::_readADC(uint16_t readmode)`
`451`	`451`	`_requestADC(readmode);`
`452`	`452`	`if (_mode == ADS1X15_MODE_SINGLE)`
`453`	`453`	`{`
`454`		`- while ( isBusy() ) yield(); // wait for conversion; yield for ESP.`
	`454`	`+ unsigned long start = millis();`
	`455`	`+ while (isBusy()) {`
	`456`	`+ yield(); // wait for conversion; yield for ESP.`
	`457`	`+ if ((start + ADS1X15_READ_TIMEOUT_MS) < millis())`
	`458`	`+ return ADS1X15_ERROR_TIMEOUT;`
	`459`	`+ }`
`455`	`460`	`}`
`456`	`461`	`else`
`457`	`462`	`{`
`@@ -737,4 +742,3 @@ void ADS1115::requestADC_Differential_2_3()`
`737`	`742`
`738`	`743`
`739`	`744`	`// -- END OF FILE --`
`740`		`-`