diff --git a/softi2c_master.c b/softi2c_master.c
index 24d85f3..04b9d11 100644
--- a/softi2c_master.c
+++ b/softi2c_master.c
@@ -20,13 +20,13 @@
 static uint16_t period = 0;
 
 // port for data line
-#define SDA_PORT GPIO_PB
+#define SDA_PORT GPIO_PD
 // pin for data line
-#define SDA_PIN PB5
+#define SDA_PIN PD2
 // port for clock line
-#define SCL_PORT GPIO_PB
+#define SCL_PORT GPIO_PD
 // pin for clock line
-#define SCL_PIN PB4
+#define SCL_PIN PD3
 // operation timeout (in half period)
 #define TIMEOUT 10U