diff --git a/hal/targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/trng_api.c b/hal/targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/trng_api.c
index c4ef754cdc..9458af27a0 100644
--- a/hal/targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/trng_api.c
+++ b/hal/targets/hal/TARGET_Freescale/TARGET_KSDK2_MCUS/TARGET_MCU_K64F/trng_api.c
@@ -22,6 +22,8 @@
  * Reference: "K64 Sub-Family Reference Manual, Rev. 2", chapter 34
  */
 
+#if defined(DEVICE_TRNG)
+
 #include <stdlib.h>
 #include "cmsis.h"
 #include "fsl_common.h"
@@ -81,3 +83,5 @@ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_l
 
     return 0;
 }
+
+#endif
diff --git a/hal/targets/hal/TARGET_NUVOTON/TARGET_NUC472/trng_api.c b/hal/targets/hal/TARGET_NUVOTON/TARGET_NUC472/trng_api.c
index 7e34c025ba..a3e8b00332 100644
--- a/hal/targets/hal/TARGET_NUVOTON/TARGET_NUC472/trng_api.c
+++ b/hal/targets/hal/TARGET_NUVOTON/TARGET_NUC472/trng_api.c
@@ -18,6 +18,7 @@
  *
  */
 
+#if DEVICE_TRNG
 
 #include <stdlib.h>
 #include <string.h>
@@ -95,5 +96,5 @@ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_l
     return 0;
 }
  
-
+#endif
 
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F4/trng_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F4/trng_api.c
index 4f7a147a39..54ac041e53 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F4/trng_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F4/trng_api.c
@@ -18,6 +18,7 @@
  *
  */
 
+#if defined(DEVICE_TRNG)
 
 #if defined(TARGET_STM32F405xx) || defined(TARGET_STM32F415xx) || defined(TARGET_STM32F407xx) || defined(TARGET_STM32F417xx) ||\
     defined(TARGET_STM32F427xx) || defined(TARGET_STM32F437xx) || defined(TARGET_STM32F429xx) || defined(TARGET_STM32F439xx) ||\
@@ -78,3 +79,4 @@ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_l
 #endif /* STM32F405xx || STM32F415xx || STM32F407xx || STM32F417xx || STM32F427xx || STM32F437xx ||\
           STM32F429xx || STM32F439xx || STM32F410xx || STM32F469xx || STM32F479xx */
 
+#endif
diff --git a/hal/targets/hal/TARGET_STM/TARGET_STM32F7/trng_api.c b/hal/targets/hal/TARGET_STM/TARGET_STM32F7/trng_api.c
index 31c5a04fc5..ef3595e9b1 100644
--- a/hal/targets/hal/TARGET_STM/TARGET_STM32F7/trng_api.c
+++ b/hal/targets/hal/TARGET_STM/TARGET_STM32F7/trng_api.c
@@ -18,6 +18,7 @@
  *
  */
 
+#if defined(DEVICE_TRNG)
 
 #include <stdlib.h>
 #include "cmsis.h"
@@ -71,3 +72,4 @@ int trng_get_bytes(trng_t *obj, uint8_t *output, size_t length, size_t *output_l
     return( ret );
 }
 
+#endif