diff --git a/IOArduino.cpp b/IOArduino.cpp
index 47f589f..759d208 100644
--- a/IOArduino.cpp
+++ b/IOArduino.cpp
@@ -30,8 +30,8 @@
 #if defined(PI_HAT_7021_REV_02)
 
 #define PIN_SCLK       PB4
-#define PIN_SREAD      PB6
-#define PIN_SDATA      PB5
+#define PIN_SREAD      PB5
+#define PIN_SDATA      PB6
 #define PIN_SLE        PB7
 #define PIN_CE         PC14
 #define PIN_RXD        PB3
diff --git a/IOSTM.cpp b/IOSTM.cpp
index f1a732d..8e1ba66 100644
--- a/IOSTM.cpp
+++ b/IOSTM.cpp
@@ -29,10 +29,10 @@
 #define PIN_SCLK             GPIO_Pin_4
 #define PORT_SCLK            GPIOB
 
-#define PIN_SREAD            GPIO_Pin_6
+#define PIN_SREAD            GPIO_Pin_5
 #define PORT_SREAD           GPIOB
 
-#define PIN_SDATA            GPIO_Pin_5
+#define PIN_SDATA            GPIO_Pin_6
 #define PORT_SDATA           GPIOB
 
 #define PIN_SLE              GPIO_Pin_7