updated afiReadWrite example code

examples/PN5180-readWriteAFI/PN5180-readWriteAFI.ino

@@ -1,60 +1,201 @@
-#include <PN5180.h>
-#include <PN5180ISO15693.h>
+// Include required libraries for NFC communication
+#include <PN5180.h>          // Base library for PN5180 NFC reader
+#include <PN5180ISO15693.h>  // Specific library for ISO15693 protocol support
 
+// Define pins based on the board type
 #if defined(ARDUINO_AVR_UNO) || defined(ARDUINO_AVR_MEGA2560) || defined(ARDUINO_AVR_NANO)
-#define PN5180_NSS  10
-#define PN5180_BUSY 9
-#define PN5180_RST  7
+// Pin definitions for Arduino boards
+#define PN5180_NSS 10  // Chip select pin
+#define PN5180_BUSY 9  // Busy status pin
+#define PN5180_RST 7   // Reset pin
 #elif defined(ARDUINO_ARCH_ESP32)
-#define PN5180_NSS  16
+// Pin definitions for ESP32 boards
+#define PN5180_NSS 16
 #define PN5180_BUSY 5
-#define PN5180_RST  17
+#define PN5180_RST 17
 #else
 #error Please define your pinout here!
 #endif
 
+// Initialize NFC reader with defined pins
 PN5180ISO15693 nfc(PN5180_NSS, PN5180_BUSY, PN5180_RST);
 
 void setup() {
+  // Initialize serial communication
   Serial.begin(115200);
-  Serial.println(F("PN5180 ISO15693 Demo"));
 
+  // Print welcome message and available commands
+  Serial.println(F("PN5180 AFI Read/Write Demo"));
+  Serial.println(F("Commands:"));
+  Serial.println(F("R - Read AFI"));
+  Serial.println(F("W - Write AFI"));
+  Serial.println(F("X - Cancel operation"));
+
+  // Initialize NFC reader
   nfc.begin();
   nfc.reset();
   nfc.setupRF();
 }
 
-void loop() {
-  uint8_t uid[8], afi;
-  if (nfc.getInventory(uid) == ISO15693_EC_OK) {
-    Serial.print(F("UID: "));
-    for (int i = 0; i < 8; i++) {
-      Serial.print(uid[7 - i], HEX);
-      if (i < 7) Serial.print(":");
+// Function to print tag's UID in hex format with colons
+void printUID(uint8_t *uid) {
+  Serial.print(F("UID: "));
+  for (int i = 0; i < 8; i++) {
+    Serial.print(uid[7 - i], HEX);  // Print in reverse order as per ISO15693 standard
+    if (i < 7) Serial.print(":");   // Add colon separator between bytes
+  }
+  Serial.println();
+}
+
+// Function to wait for a tag to be presented
+// Returns true if tag is found, false if operation is cancelled
+bool waitForTag(uint8_t *uid) {
+  Serial.println(F("Waiting for tag... (Press X to cancel)"));
+  while (true) {
+    // Check for cancel command
+    if (Serial.available()) {
+      char input = Serial.read();
+      while (Serial.available()) Serial.read();  // Clear buffer
+      if (input == 'X' || input == 'x') {
+        Serial.println(F("Operation cancelled"));
+        return false;
+      }
     }
-    Serial.println();
 
-    nfc.readAFI(uid, &afi);
-    Serial.print("Current AFI: ");
+    // Try to detect tag
+    if (nfc.getInventory(uid) == ISO15693_EC_OK) {
+      printUID(uid);
+      return true;
+    }
+    delay(100);  // Small delay to prevent CPU hogging
+  }
+}
+
+// Function to read AFI value from tag
+void readAFIValue() {
+  uint8_t uid[8], afi;
+
+  // Wait for tag to be presented
+  if (!waitForTag(uid)) {
+    return;
+  }
+
+  // Try to read AFI value
+  if (nfc.readAFI(uid, &afi) == ISO15693_EC_OK) {
+    Serial.print(F("Current AFI: "));
     Serial.println(afi, HEX);
+  } else {
+    Serial.println(F("Failed to read AFI value"));
+  }
+}
 
-    delay(1000); // Wait 1 second
+// Function to read user input from Serial
+// Returns complete string without newline characters
+String readSerialInput() {
+  String input = "";
 
-    Serial.println(F("Enter new AFI value (in hex, e.g., CC):"));
-    while (Serial.available() == 0) {
-      // Wait for user input
-    }
-    String afiInput = Serial.readStringUntil('\n');
-    uint8_t afiValue = (uint8_t) strtol(afiInput.c_str(), NULL, 16);
+  // Wait for data to be available
+  while (!Serial.available()) {
+    delay(10);
+  }
 
-    if (nfc.writeAFI(uid, afiValue) == ISO15693_EC_OK) {
-      Serial.println(F("AFI value written successfully"));
+  // Read characters until newline
+  while (Serial.available()) {
+    char c = Serial.read();
+    if (c == '\n' || c == '\r') {
+      if (input.length() > 0) {
+        break;
+      }
     } else {
-      Serial.println(F("Failed to write AFI value"));
+      input += c;
+    }
+    delay(2);  // Small delay for reliable serial reading
+  }
+
+  while (Serial.available()) Serial.read();  // Clear remaining buffer
+  return input;
+}
+
+// Function to write new AFI value to tag
+void writeAFIValue() {
+  uint8_t uid[8];
+
+  Serial.println(F("Enter new AFI value (in hex, e.g., CC):"));
+  String afiInput = readSerialInput();
+
+  // Validate input is valid hexadecimal
+  for (unsigned int i = 0; i < afiInput.length(); i++) {
+    if (!isHexadecimalDigit(afiInput.charAt(i))) {
+      Serial.println(F("Invalid hex value entered. Operation cancelled."));
+      return;
     }
+  }
+
+  // Convert hex string to byte
+  uint8_t afiValue = (uint8_t)strtol(afiInput.c_str(), NULL, 16);
+
+  // Wait for tag
+  if (!waitForTag(uid)) {
+    return;
+  }
+
+  // Try to write new AFI value
+  if (nfc.writeAFI(uid, afiValue) == ISO15693_EC_OK) {
+    Serial.println(F("AFI value written successfully"));
+    delay(100);  // Small delay before next operation
   } else {
-    Serial.println(F("No tag detected"));
+    Serial.println(F("Failed to write AFI value"));
+  }
+}
+
+// Function to read single command character from Serial
+char readCommand() {
+  String input = "";
+
+  // Wait for input
+  while (!Serial.available()) {
+    delay(10);
+  }
+
+  // Read until newline, ignoring CR/LF
+  while (Serial.available()) {
+    char c = Serial.read();
+    if (c != '\n' && c != '\r') {
+      input += c;
+    }
+    delay(2);
+  }
+
+  // Clear any remaining characters
+  while (Serial.available()) {
+    Serial.read();
+  }
+
+  // Return first character or null if empty
+  return input.length() > 0 ? input[0] : '\0';
+}
+
+// Main program loop
+void loop() {
+  Serial.println(F("\nEnter command (R/W):"));
+  char command = readCommand();
+
+  // Process command
+  switch (command) {
+    case 'R':
+    case 'r':
+      readAFIValue();
+      break;
+    case 'W':
+    case 'w':
+      writeAFIValue();
+      break;
+    case '\0':  // Empty input
+      break;
+    default:
+      Serial.println(F("Invalid command. Use 'R' for read or 'W' for write."));
+      break;
   }
 
-  delay(1000); // Wait 1 second before checking again
+  delay(100);  // Small delay before next command
 }