diff --git a/crc16.h b/crc16.h
index 5ad7f806..f5f58659 100644
--- a/crc16.h
+++ b/crc16.h
@@ -57,6 +57,7 @@ namespace etl
   public:
 
     typedef uint16_t value_type;
+    typedef uint16_t argument_type;
 
     //*************************************************************************
     /// Default constructor.
diff --git a/crc16_ccitt.h b/crc16_ccitt.h
index a7cdeab8..b6b5ade6 100644
--- a/crc16_ccitt.h
+++ b/crc16_ccitt.h
@@ -57,6 +57,7 @@ namespace etl
   public:
 
     typedef uint16_t value_type;
+    typedef uint16_t argument_type;
 
     //*************************************************************************
     /// Default constructor.
diff --git a/crc16_kermit.h b/crc16_kermit.h
index 3de579dd..73d1c42e 100644
--- a/crc16_kermit.h
+++ b/crc16_kermit.h
@@ -57,6 +57,7 @@ namespace etl
   public:
 
     typedef uint16_t value_type;
+    typedef uint16_t argument_type;
 
     //*************************************************************************
     /// Default constructor.
diff --git a/crc32.h b/crc32.h
index 1a2c494d..7f800936 100644
--- a/crc32.h
+++ b/crc32.h
@@ -57,6 +57,7 @@ namespace etl
   public:
 
     typedef uint32_t value_type;
+    typedef uint32_t argument_type;
 
     //*************************************************************************
     /// Default constructor.
diff --git a/crc64_ecma.h b/crc64_ecma.h
index 5d3d063b..5279ec6c 100644
--- a/crc64_ecma.h
+++ b/crc64_ecma.h
@@ -57,6 +57,7 @@ namespace etl
   public:
 
     typedef uint64_t value_type;
+    typedef uint64_t argument_type;
 
     //*************************************************************************
     /// Default constructor.
diff --git a/crc8_ccitt.h b/crc8_ccitt.h
index 2c473cbc..d0b4e806 100644
--- a/crc8_ccitt.h
+++ b/crc8_ccitt.h
@@ -57,6 +57,7 @@ namespace etl
   public:
 
     typedef uint8_t value_type;
+    typedef uint8_t argument_type;
 
     //*************************************************************************
     /// Default constructor.