diff --git a/coresdk/src/coresdk/raspi_gpio.cpp b/coresdk/src/coresdk/raspi_gpio.cpp
index 610c1793..cb816639 100644
--- a/coresdk/src/coresdk/raspi_gpio.cpp
+++ b/coresdk/src/coresdk/raspi_gpio.cpp
@@ -232,7 +232,7 @@ namespace splashkit_lib
 #endif
     }
 
-    int raspi_spi_transfer(int handle, char *sendBuf, char *recvBuf, int count)
+    int raspi_spi_transfer(int handle, string sendBuf, string recvBuf, int count)
     {
 #ifdef RASPBERRY_PI
         return sk_spi_transfer(handle, sendBuf, recvBuf, count);
diff --git a/coresdk/src/coresdk/raspi_gpio.h b/coresdk/src/coresdk/raspi_gpio.h
index 57f75d69..2b61672d 100644
--- a/coresdk/src/coresdk/raspi_gpio.h
+++ b/coresdk/src/coresdk/raspi_gpio.h
@@ -142,7 +142,7 @@ namespace splashkit_lib
      * @param count    The number of bytes to be transferred.
      * @returns        The number of bytes that have actually been transfered.
      */
-    int raspi_spi_transfer(int handle, char *sendBuf, char *recvBuf, int count);
+    int raspi_spi_transfer(int handle, string sendBuf, string recvBuf, int count);
 	
     /**
      * @brief Cleans up and releases any resources used by the GPIO library.