Add monotonic counter support

examples/ECCX08Counter/ECCX08Counter.ino

@@ -0,0 +1,43 @@
+/*
+  ECCX08 Counter
+
+  This sketch uses the ECC508 or ECC608 to increment a monotonic 
+  counter at each startup
+
+  Circuit:
+   - Any board with ECC508 or ECC608 on board
+
+*/
+
+#include <ArduinoECCX08.h>
+
+const int keyId = 5;
+long counter = -1;
+
+void setup() {
+  Serial.begin(9600);
+  while (!Serial);
+
+  if (!ECCX08.begin()) {
+    Serial.println("Failed to communicate with ECC508/ECC608!");
+    while (1);
+  }
+
+  if (!ECCX08.incrementCounter(keyId, counter)) {
+    Serial.println("Failed to increment counter");
+    while (1);
+  }
+}
+
+void loop() {
+  if (!ECCX08.readCounter(keyId, counter)) {
+    Serial.println("Failed to read counter");
+    while (1);
+  }
+
+  Serial.print("Counter value = ");
+  Serial.println(counter);
+
+  delay(1000);
+}
+

src/ECCX08.cpp

@@ -548,6 +548,80 @@ int ECCX08Class::nonce(const byte data[])
   return challenge(data);
 }
 
+int ECCX08Class::incrementCounter(int counterId, long& counter)
+{
+  if (counterId < 0 || counterId > 1) {
+    return 0;
+  }
+
+  if (!wakeup()) {
+    return 0;
+  }
+
+  if (!sendCommand(0x24, 1, counterId)) {
+    return 0;
+  }
+
+  delay(20);
+
+  if (!receiveResponse(&counter, sizeof(counter))) {
+    return 0;
+  }
+
+  delay(1);
+  idle();
+
+  return 1;
+}
+
+long ECCX08Class::incrementCounter(int counterId)
+{
+  long counter;  // the counter can go up to 2,097,151
+
+  if(!incrementCounter(counterId, counter)) {
+    return -1;
+  }
+
+  return counter;
+}
+
+int ECCX08Class::readCounter(int counterId, long& counter)
+{
+  if (counterId < 0 || counterId > 1) {
+    return 0;
+  }
+
+  if (!wakeup()) {
+    return 0;
+  }
+
+  if (!sendCommand(0x24, 0, counterId)) {
+    return 0;
+  }
+
+  delay(20);
+
+  if (!receiveResponse(&counter, sizeof(counter))) {
+    return 0;
+  }
+
+  delay(1);
+  idle();
+
+  return 1;
+}
+
+long ECCX08Class::readCounter(int counterId)
+{
+  long counter;  // the counter can go up to 2,097,151
+
+  if(!readCounter(counterId, counter)) {
+    return -1;
+  }
+
+  return counter;
+}
+
 int ECCX08Class::wakeup()
 {
   _wire->setClock(_wakeupFrequency);
@@ -892,4 +966,4 @@ uint16_t ECCX08Class::crc16(const byte data[], size_t length)
 ECCX08Class ECCX08(CRYPTO_WIRE, 0x60);
 #else
 ECCX08Class ECCX08(Wire, 0x60);
-#endif
+#endif

src/ECCX08.h

@@ -66,6 +66,11 @@ class ECCX08Class
 
   int nonce(const byte data[]);
 
+  int incrementCounter(int counterId, long& counter);
+  long incrementCounter(int counterId);
+  int readCounter(int counterId, long& counter);
+  long readCounter(int counterId);
+
 private:
   int wakeup();
   int sleep();