diff --git a/src/MFRC522.h b/src/MFRC522.h
index 5ebbd27..597c4a5 100644
--- a/src/MFRC522.h
+++ b/src/MFRC522.h
@@ -19,7 +19,7 @@
 #include <SPI.h>
 
 #ifndef MFRC522_SPICLOCK
-#define MFRC522_SPICLOCK SPI_CLOCK_DIV4			// MFRC522 accept upto 10MHz
+#define MFRC522_SPICLOCK (4000000u)	// MFRC522 accept upto 10MHz, set to 4MHz.
 #endif
 
 // Firmware data for self-test