diff --git a/src/stm32-i2s.cpp b/src/stm32-i2s.cpp
index 4265bd6..a987107 100644
--- a/src/stm32-i2s.cpp
+++ b/src/stm32-i2s.cpp
@@ -1,6 +1,8 @@
 
 #include "stm32-i2s.h"
 
+#ifdef STM_I2S_PINS
+
 namespace stm32_i2s {
 
 //Stm32I2sClass I2S;
@@ -92,3 +94,6 @@ extern "C" void assert_failed(uint8_t *file, uint32_t line) {
 #endif /* USE_FULL_ASSERT */
 
 }
+
+#endif // STM_I2S_PINS
+
diff --git a/src/stm32-i2s.h b/src/stm32-i2s.h
index ccdeb0e..658c40a 100644
--- a/src/stm32-i2s.h
+++ b/src/stm32-i2s.h
@@ -28,6 +28,9 @@
 #  include "stm32f4xx_hal.h"
 #endif
 
+#ifdef STM_I2S_PINS
+
+
 extern uint32_t g_anOutputPinConfigured[MAX_NB_PORT];
 
 namespace stm32_i2s {
@@ -645,3 +648,7 @@ void STM32_LOG(const char *msg) {
 //extern Stm32I2sClass I2S;
 
 }  // namespace stm32_i2s
+
+#else
+#warning STM_I2S_PINS not defined
+#endif