diff --git a/include/globals.h b/include/globals.h
index f8ef5fa5..01f912ff 100644
--- a/include/globals.h
+++ b/include/globals.h
@@ -36,7 +36,7 @@
 #define SCREEN_MODE (0x80)
 
 // I2C bus access control
-#define I2C_MUTEX_LOCK()    xSemaphoreTake(I2Caccess, (DISPLAYREFRESH_MS / portTICK_PERIOD_MS)) != pdTRUE
+#define I2C_MUTEX_LOCK()    xSemaphoreTake(I2Caccess, (DISPLAYREFRESH_MS / portTICK_PERIOD_MS)) == pdTRUE
 #define I2C_MUTEX_UNLOCK()  xSemaphoreGive(I2Caccess)
 
 // Struct holding devices's runtime configuration