From 9232f8594bc7bc7602e2dfbde0cb0bb48a7e5a9e Mon Sep 17 00:00:00 2001
From: lahiru <lahirunirmalx@gmail.com>
Date: Thu, 22 Jan 2026 11:28:36 +0530
Subject: [PATCH] fix(critical): add timeout to DRDY wait functions to prevent
 infinite hang

- waitForLowDRDY() and waitForHighDRDY() now accept timeout_ms parameter (default 1000ms)
- Returns false if timeout occurs, true on success
- Added _lastOpTimeout flag to track timeout state
- Added hasTimeout() public method to check if last operation timed out
- Prevents MCU from hanging indefinitely when hardware fails or disconnects
---
 src/ADS1256.cpp | 37 ++++++++++++++++++++++++++++++-------
 src/ADS1256.h   |  8 ++++++--
 2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/src/ADS1256.cpp b/src/ADS1256.cpp
index 3372b47..e0f7000 100644
--- a/src/ADS1256.cpp
+++ b/src/ADS1256.cpp
@@ -19,7 +19,7 @@
 
 //Constructor
 ADS1256::ADS1256(const int8_t DRDY_pin, const int8_t RESET_pin, const int8_t SYNC_pin, const int8_t CS_pin,float VREF, SPIClass* spi):  _spi(spi),
-  _DRDY_pin(DRDY_pin),  _RESET_pin(RESET_pin),  _SYNC_pin(SYNC_pin),  _CS_pin(CS_pin),  _VREF(VREF),  _PGA(0)
+  _DRDY_pin(DRDY_pin),  _RESET_pin(RESET_pin),  _SYNC_pin(SYNC_pin),  _CS_pin(CS_pin),  _VREF(VREF),  _PGA(0),  _lastOpTimeout(false)
 {	
 	pinMode(_DRDY_pin, INPUT);	
 	 
@@ -94,16 +94,39 @@ void ADS1256::InitializeADC()
   _isAcquisitionRunning = false; //MCU will be waiting to start a continuous acquisition
 }
 
-void ADS1256::waitForLowDRDY()
-{		    
-    while (digitalRead(_DRDY_pin) == HIGH) {} 
+bool ADS1256::waitForLowDRDY(unsigned long timeout_ms)
+{
+    unsigned long start = millis();
+    while (digitalRead(_DRDY_pin) == HIGH) {
+        if (millis() - start >= timeout_ms) {
+            _lastOpTimeout = true;
+            return false; // Timeout occurred
+        }
+    }
+    return true; // DRDY went low
 }
 
-void ADS1256::waitForHighDRDY()
-{		
+bool ADS1256::waitForHighDRDY(unsigned long timeout_ms)
+{
 #if F_CPU >= 48000000  //Fast MCUs need this protection to wait until DRDY goes high after a conversion
-	while (digitalRead(_DRDY_pin) == LOW) {}   
+    unsigned long start = millis();
+    while (digitalRead(_DRDY_pin) == LOW) {
+        if (millis() - start >= timeout_ms) {
+            _lastOpTimeout = true;
+            return false; // Timeout occurred
+        }
+    }
+#else
+    (void)timeout_ms; // Suppress unused parameter warning on slow MCUs
 #endif
+    return true; // DRDY went high (or not needed on slow MCUs)
+}
+
+bool ADS1256::hasTimeout()
+{
+    bool timeout = _lastOpTimeout;
+    _lastOpTimeout = false; // Clear flag after reading
+    return timeout;
 }
 
 void ADS1256::stopConversion() //Sending SDATAC to stop the continuous conversion
diff --git a/src/ADS1256.h b/src/ADS1256.h
index 1ded2e2..8a6f796 100644
--- a/src/ADS1256.h
+++ b/src/ADS1256.h
@@ -151,12 +151,15 @@ static constexpr int8_t PIN_UNUSED = -1;
 	//Stop AD
 	void stopConversion();
 	
+	//Check if last operation timed out waiting for DRDY
+	bool hasTimeout();
+	
 private:
 	
 SPIClass* _spi; //Pointer to an SPIClass object
 
-void waitForLowDRDY(); // Block until DRDY is low
-void waitForHighDRDY(); // Block until DRDY is high
+bool waitForLowDRDY(unsigned long timeout_ms = 1000); // Block until DRDY is low, returns false on timeout
+bool waitForHighDRDY(unsigned long timeout_ms = 1000); // Block until DRDY is high, returns false on timeout
 void updateMUX(uint8_t muxValue);
 inline void CS_LOW();
 inline void CS_HIGH();
@@ -185,5 +188,6 @@ byte _outputBuffer[3]; //3-byte (24-bit) buffer for the fast acquisition - Singl
 long _outputValue; //Combined value of the _outputBuffer[3]
 bool _isAcquisitionRunning; //bool that keeps track of the acquisition (running or not)
 uint8_t _cycle; //Tracks the cycles as the MUX is cycling through the input channels
+bool _lastOpTimeout; //Tracks if last DRDY wait timed out
 };
 #endif
\ No newline at end of file