diff --git a/README b/README
index 1ea67ad0c..5ae5971f6 100644
--- a/README
+++ b/README
@@ -32,6 +32,14 @@ SSL_CTX_set_verify(ctx, SSL_VERIFY_NONE, 0);
 
 before calling SSL_new();  Though it's not recommended.
 
+
+Note 3)
+CyaSSL is able to use the STM32F2 hardware-based cryptography and random number
+generator through the STM32F2 Standard Peripheral Library. For necessary
+defines, see the CYASSL_STM32F2 define in settings.h. Documentation for the
+STM32F2 Standard Peripheral Library can be found in the following document: 
+http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/USER_MANUAL/DM00023896.pdf
+
 *** end Notes ***
 
 
diff --git a/cyassl/ctaocrypt/settings.h b/cyassl/ctaocrypt/settings.h
index ccdcd8eb7..c8075760e 100644
--- a/cyassl/ctaocrypt/settings.h
+++ b/cyassl/ctaocrypt/settings.h
@@ -66,6 +66,9 @@
 /* Uncomment next line if building CyaSSL for Freescale MQX/RTCS/MFS */
 /* #define FREESCALE_MQX */
 
+/* Uncomment next line if using STM32F2 */
+/* #define CYASSL_STM32F2 */
+
 
 #include <cyassl/ctaocrypt/visibility.h>
 
@@ -226,6 +229,16 @@
     /* Note: MQX has no realloc, using fastmath above */
 #endif
 
+#ifdef CYASSL_STM32F2
+    #define SIZEOF_LONG_LONG 8
+    #define NO_DEV_RANDOM
+    #define NO_CYASSL_DIR
+    #define NO_RABBIT
+    #define STM32F2_RNG
+    #define STM32F2_CRYPTO
+    #define KEIL_INTRINSICS
+#endif
+
 #ifdef MICRIUM
 
     #include "stdlib.h"
diff --git a/src/io.c b/src/io.c
index 6bd4c3b60..a6344ebfd 100644
--- a/src/io.c
+++ b/src/io.c
@@ -45,6 +45,7 @@
         /* lwIP needs to be configured to use sockets API in this mode */
         /* LWIP_SOCKET 1 in lwip/opt.h or in build */
         #include "lwip/sockets.h"
+        #include <errno.h>
         #ifndef LWIP_PROVIDE_ERRNO
             #define LWIP_PROVIDE_ERRNO 1
         #endif