diff --git a/src/bill-acceptor.cpp b/src/bill-acceptor.cpp
index 45bd769..a96b1d2 100644
--- a/src/bill-acceptor.cpp
+++ b/src/bill-acceptor.cpp
@@ -2,7 +2,13 @@
 
 namespace {
 
-	bool initialized = false;
+	enum class State {
+		uninitialized,
+		initialized,
+		failed
+	};
+	State state = State::uninitialized;
+
 	std::deque<int> buffer;
 	float accumulatedValue = 0.00;
 	float escrowValue = 0.00;
@@ -91,10 +97,12 @@ namespace {
 	}
 
 	void serialWriteSIOCode(const char* key) {
-		const uint8_t byteOut = getSIOCodeByte(key);
-		if (byteOut > 0) {
-			logger::write("Sending SIO code to bill acceptor: \"" + std::string(key) + "\"");
-			Serial1.write(byteOut);
+		if (state == State::initialized) {
+			const uint8_t byteOut = getSIOCodeByte(key);
+			if (byteOut > 0) {
+				logger::write("Sending SIO code to bill acceptor: \"" + std::string(key) + "\"");
+				Serial1.write(byteOut);
+			}
 		}
 	}
 
@@ -154,7 +162,7 @@ namespace billAcceptor {
 	}
 
 	void loop() {
-		if (initialized) {
+		if (state == State::initialized) {
 			while (Serial1.available()) {
 				const uint8_t byteIn = Serial1.read();
 				if (byteIn > 0) {
@@ -166,19 +174,24 @@ namespace billAcceptor {
 				}
 			}
 			parseBuffer();
-		} else if (!(billRxPin > 0)) {
-			logger::write("Cannot initialize bill acceptor: \"billRxPin\" not set");
-		} else if (!(billTxPin > 0)) {
-			logger::write("Cannot initialize bill acceptor: \"billTxPin\" not set");
-		} else if (!(billBaudRate > 0)) {
-			logger::write("Cannot initialize bill acceptor: \"billBaudRate\" not set");
-		} else {
-			initialized = true;
-			logger::write("Initializing bill acceptor...");
-			Serial1.begin(billBaudRate, SERIAL_8N1, billTxPin, billRxPin);
-			billAcceptor::disinhibit();
-			serialWriteSIOCode("enable_escrow_mode");
-			serialWriteSIOCode("enable_escrow_timeout");
+		} else if (state == State::uninitialized) {
+			if (!(billRxPin > 0)) {
+				logger::write("Cannot initialize bill acceptor: \"billRxPin\" not set", "warn");
+				state = State::failed;
+			} else if (!(billTxPin > 0)) {
+				logger::write("Cannot initialize bill acceptor: \"billTxPin\" not set", "warn");
+				state = State::failed;
+			} else if (!(billBaudRate > 0)) {
+				logger::write("Cannot initialize bill acceptor: \"billBaudRate\" not set", "warn");
+				state = State::failed;
+			} else {
+				logger::write("Initializing bill acceptor...");
+				Serial1.begin(billBaudRate, SERIAL_8N1, billTxPin, billRxPin);
+				billAcceptor::disinhibit();
+				serialWriteSIOCode("enable_escrow_mode");
+				serialWriteSIOCode("enable_escrow_timeout");
+				state = State::initialized;
+			}
 		}
 	}
 
diff --git a/src/button.cpp b/src/button.cpp
index d3b6ac8..acff366 100644
--- a/src/button.cpp
+++ b/src/button.cpp
@@ -1,6 +1,14 @@
 #include "button.h"
 
 namespace {
+
+	enum class State {
+		uninitialized,
+		initialized,
+		failed
+	};
+	State state = State::uninitialized;
+
 	bool pressed = false;
 	int lastState;
 	unsigned long lastStateChangeTime = 0;// Last time the button pin was toggled.
@@ -11,27 +19,35 @@ namespace {
 namespace button {
 
 	void init() {
-		logger::write("Initializing button...");
-		debounceDelay = config::getUnsignedInt("buttonDebounce");
 		pinNumber = config::getUnsignedShort("buttonPin");
-		pinMode(pinNumber, INPUT);
+		debounceDelay = config::getUnsignedInt("buttonDebounce");
+		if (!(pinNumber > 0)) {
+			logger::write("Cannot initialize button: \"buttonPin\" not set", "warn");
+			state = State::failed;
+		} else {
+			logger::write("Initializing button...");
+			pinMode(pinNumber, INPUT);
+			state = State::initialized;
+		}
 	}
 
 	void loop() {
-		if ((millis() - lastStateChangeTime) > debounceDelay) {
-			const int state = digitalRead(pinNumber);
-			if (state != lastState) {
-				if (state == HIGH) {
-					pressed = true;
-					logger::write("Button pressed");
-				} else {
-					pressed = false;
-					logger::write("Button released");
+		if (state == State::initialized) {
+			if (millis() - lastStateChangeTime > debounceDelay) {
+				const int state = digitalRead(pinNumber);
+				if (state != lastState) {
+					if (state == HIGH) {
+						pressed = true;
+						logger::write("Button pressed");
+					} else {
+						pressed = false;
+						logger::write("Button released");
+					}
+					// Reset the debouncing timer.
+					// We track time in order to avoid noise state changes.
+					lastStateChangeTime = millis();
+					lastState = state;
 				}
-				// Reset the debouncing timer.
-				// We track time in order to avoid noise state changes.
-				lastStateChangeTime = millis();
-				lastState = state;
 			}
 		}
 	}
diff --git a/src/coin-acceptor/dg600f.cpp b/src/coin-acceptor/dg600f.cpp
index 02c06cc..5d3fb7c 100644
--- a/src/coin-acceptor/dg600f.cpp
+++ b/src/coin-acceptor/dg600f.cpp
@@ -2,13 +2,20 @@
 
 namespace {
 
-	bool initialized = false;
+	enum class State {
+		uninitialized,
+		initialized,
+		failed
+	};
+	State state = State::uninitialized;
+
 	float accumulatedValue = 0.00;
 	std::deque<int> buffer;
 	std::vector<float> coinValues;
 	unsigned short coinSignalPin;
 	unsigned short coinInhibitPin;
 	unsigned int coinBaudRate;
+	unsigned short fiatPrecision;
 
 	float getCoinValue(const int &byteIn) {
 		const int index = byteIn - 1;
@@ -34,7 +41,7 @@ namespace {
 					const int byte3 = buffer.front();
 					buffer.pop_front();
 					if (byte3 == (byte1 ^ byte2)) {
-						logger::write("Coin inserted with value = " + std::to_string(coinValue));
+						logger::write("Coin inserted with value = " + util::floatToStringWithPrecision(coinValue, fiatPrecision));
 						accumulatedValue += coinValue;
 					}
 				}
@@ -50,10 +57,11 @@ namespace coinAcceptor_dg600f {
 		coinInhibitPin = config::getUnsignedShort("coinInhibitPin");
 		coinBaudRate = config::getUnsignedInt("coinBaudRate");
 		coinValues = config::getFloatVector("coinValues");
+		fiatPrecision = config::getUnsignedShort("fiatPrecision");
 	}
 
 	void loop() {
-		if (initialized) {
+		if (state == State::initialized) {
 			while (Serial2.available()) {
 				const int byteReceived = Serial2.read();
 				if (byteReceived > 0 && byteReceived < 254) {
@@ -61,18 +69,23 @@ namespace coinAcceptor_dg600f {
 				}
 			}
 			parseBuffer();
-		} else if (!(coinSignalPin > 0)) {
-			logger::write("Cannot initialize coin acceptor: \"coinSignalPin\" not set");
-		} else if (!(coinInhibitPin > 0)) {
-			logger::write("Cannot initialize coin acceptor: \"coinInhibitPin\" not set");
-		} else if (!(coinBaudRate > 0)) {
-			logger::write("Cannot initialize coin acceptor: \"coinBaudRate\" not set");
-		} else {
-			logger::write("Initializing DG600F coin acceptor...");
-			initialized = true;
-			Serial2.begin(coinBaudRate, SERIAL_8E1, coinSignalPin, 0);
-			pinMode(coinInhibitPin, OUTPUT);
-			coinAcceptor_dg600f::disinhibit();
+		} else if (state == State::uninitialized) {
+			if (!(coinSignalPin > 0)) {
+				logger::write("Cannot initialize coin acceptor: \"coinSignalPin\" not set", "warn");
+				state = State::failed;
+			} else if (!(coinInhibitPin > 0)) {
+				logger::write("Cannot initialize coin acceptor: \"coinInhibitPin\" not set", "warn");
+				state = State::failed;
+			} else if (!(coinBaudRate > 0)) {
+				logger::write("Cannot initialize coin acceptor: \"coinBaudRate\" not set", "warn");
+				state = State::failed;
+			} else {
+				logger::write("Initializing DG600F coin acceptor...");
+				Serial2.begin(coinBaudRate, SERIAL_8E1, coinSignalPin, 0);
+				pinMode(coinInhibitPin, OUTPUT);
+				coinAcceptor_dg600f::disinhibit();
+				state = State::initialized;
+			}
 		}
 	}
 
@@ -85,10 +98,14 @@ namespace coinAcceptor_dg600f {
 	}
 
 	void inhibit() {
-		digitalWrite(coinInhibitPin, LOW);
+		if (state == State::initialized) {
+			digitalWrite(coinInhibitPin, LOW);
+		}
 	}
 
 	void disinhibit() {
-		digitalWrite(coinInhibitPin, HIGH);
+		if (state == State::initialized) {
+			digitalWrite(coinInhibitPin, HIGH);
+		}
 	}
 }
diff --git a/src/coin-acceptor/hx616.cpp b/src/coin-acceptor/hx616.cpp
index cc2a501..3bdcf8c 100644
--- a/src/coin-acceptor/hx616.cpp
+++ b/src/coin-acceptor/hx616.cpp
@@ -2,7 +2,13 @@
 
 namespace {
 
-	bool initialized = false;
+	enum class State {
+		uninitialized,
+		initialized,
+		failed
+	};
+	State state = State::uninitialized;
+
 	float valueIncrement = 1.00;
 	float accumulatedValue = 0.00;
 	uint8_t lastPinReadState;
@@ -37,7 +43,7 @@ namespace coinAcceptor_hx616 {
 	}
 
 	void loop() {
-		if (initialized) {
+		if (state == State::initialized) {
 			if (pinStateHasChanged()) {
 				if (coinWasInserted()) {
 					// This code executes once for each pulse from the HX-616.
@@ -46,13 +52,16 @@ namespace coinAcceptor_hx616 {
 				}
 				flipPinState();
 			}
-		} else if (!(coinSignalPin > 0)) {
-			logger::write("Cannot initialize coin acceptor: \"coinSignalPin\" not set");
-		} else {
-			logger::write("Initializing HX616 coin acceptor...");
-			initialized = true;
-			pinMode(coinSignalPin, INPUT_PULLUP);
-			lastPinReadState = readPin();
+		} else if (state == State::uninitialized) {
+			if (!(coinSignalPin > 0)) {
+				logger::write("Cannot initialize coin acceptor: \"coinSignalPin\" not set", "warn");
+				state = State::failed;
+			} else {
+				logger::write("Initializing HX616 coin acceptor...");
+				pinMode(coinSignalPin, INPUT_PULLUP);
+				lastPinReadState = readPin();
+				state = State::initialized;
+			}
 		}
 	}