diff --git a/common/iso15693tools.c b/common/iso15693tools.c
index 7ee52d450..05a4bfc3d 100644
--- a/common/iso15693tools.c
+++ b/common/iso15693tools.c
@@ -72,22 +72,22 @@ char* Iso15693sprintUID(char *target, uint8_t *uid) {
 	return target;
 }
 
-uint16_t iclass_crc16(char *data_p, unsigned short length) {
-	unsigned char i;
+uint16_t iclass_crc16(uint8_t *d, uint16_t n) {
+
 	unsigned int data;
 	uint16_t crc = 0xffff;
 
-	if (length == 0)
+	if (n == 0)
 		return (~crc);
 
 	do {
-		for (i=0, data = (unsigned int)0xff & *data_p++; i < 8;  i++, data >>= 1) {
+		for (uint8_t i=0, data = *d++; i < 8;  i++, data >>= 1) {
 			if ((crc & 0x0001) ^ (data & 0x0001))
 				crc = (crc >> 1) ^ POLY;
 			else  
 				crc >>= 1;
 		}
-	} while (--length);
+	} while (--n);
 
 	crc = ~crc;
 	data = crc;
diff --git a/common/iso15693tools.h b/common/iso15693tools.h
index a0b50974b..66e9ae35f 100644
--- a/common/iso15693tools.h
+++ b/common/iso15693tools.h
@@ -78,7 +78,8 @@ uint16_t Iso15693Crc(uint8_t *v, int n);
 int Iso15693AddCrc(uint8_t *req, int n);
 bool Iso15693CheckCrc(uint8_t *d, int n);
 char* Iso15693sprintUID(char *target,uint8_t *uid);
-unsigned short iclass_crc16(char *data_p, unsigned short length);
+
+uint16_t iclass_crc16(uint8_t *d, uint16_t n);
 
 //-----------------------------------------------------------------------------
 // Map a sequence of octets (~layer 2 command) into the set of bits to feed