diff --git a/STM32F1/libraries/SPI/src/SPI.h b/STM32F1/libraries/SPI/src/SPI.h
index 571b03350..2638cda83 100644
--- a/STM32F1/libraries/SPI/src/SPI.h
+++ b/STM32F1/libraries/SPI/src/SPI.h
@@ -277,7 +277,7 @@ class SPIClass {
     // Some libraries (like recent Adafruit graphics libraries) require
     // the write function be availabe under the name transfer, so here it is:
     inline void transfer(const void * buffer, size_t length) {
-     write((uint32_t)buffer, length);
+     write(buffer, (uint32)length);
     }
  
     /**