diff --git a/arch/arm/src/stm32/stm32_dfumode.c b/arch/arm/src/stm32/stm32_dfumode.c
index 28c2d8f6611..fd99a1bb809 100644
--- a/arch/arm/src/stm32/stm32_dfumode.c
+++ b/arch/arm/src/stm32/stm32_dfumode.c
@@ -44,6 +44,8 @@
 #include <unistd.h>
 #include <debug.h>
 
+#include <nuttx/signal.h>
+
 #include "stm32_dfumode.h"
 
 /****************************************************************************
@@ -73,7 +75,7 @@ void stm32_dfumode(void)
 {
 #ifdef CONFIG_DEBUG_WARN
   _warn("Entering DFU mode...\n");
-  sleep(1);
+  nxsig_sleep(1);
 #endif
 
   asm("ldr r0, =0x40023844\n\t"    /* RCC_APB2ENR */
diff --git a/boards/arm/stm32/nucleo-f302r8/src/stm32_highpri.c b/boards/arm/stm32/nucleo-f302r8/src/stm32_highpri.c
index c043ceb493d..6e8e927957f 100644
--- a/boards/arm/stm32/nucleo-f302r8/src/stm32_highpri.c
+++ b/boards/arm/stm32/nucleo-f302r8/src/stm32_highpri.c
@@ -504,7 +504,7 @@ int highpri_main(int argc, char *argv[])
 
       adc1->ad_ops->ao_ioctl(adc1, IO_TRIGGER_REG, 0);
 
-      nxsig_usleep(100);
+      usleep(100);
 #endif
 
 #ifdef HIGHPRI_HAVE_INJECTED
@@ -512,7 +512,7 @@ int highpri_main(int argc, char *argv[])
 
       adc1->ad_ops->ao_ioctl(adc1, IO_TRIGGER_INJ, 0);
 
-      nxsig_usleep(100);
+      usleep(100);
 #endif
       /* Lock global data */
 
@@ -548,7 +548,7 @@ int highpri_main(int argc, char *argv[])
 
       g_highpri.lock = false;
 
-      sleep(1);
+      nxsig_sleep(1);
     }
 
 errout:
diff --git a/boards/arm/stm32/nucleo-f334r8/src/stm32_highpri.c b/boards/arm/stm32/nucleo-f334r8/src/stm32_highpri.c
index eb8ac8b01ed..bce067d762a 100644
--- a/boards/arm/stm32/nucleo-f334r8/src/stm32_highpri.c
+++ b/boards/arm/stm32/nucleo-f334r8/src/stm32_highpri.c
@@ -546,7 +546,7 @@ int highpri_main(int argc, char *argv[])
 
       adc1->ad_ops->ao_ioctl(adc1, IO_TRIGGER_REG, 0);
 
-      nxsig_usleep(100);
+      usleep(100);
 #endif
 
 #ifdef HIGHPRI_HAVE_INJECTED
@@ -554,7 +554,7 @@ int highpri_main(int argc, char *argv[])
 
       adc1->ad_ops->ao_ioctl(adc1, IO_TRIGGER_INJ, 0);
 
-      nxsig_usleep(100);
+      usleep(100);
 #endif
       /* Lock global data */
 
@@ -590,7 +590,7 @@ int highpri_main(int argc, char *argv[])
 
       g_highpri.lock = false;
 
-      sleep(1);
+      nxsig_sleep(1);
     }
 
 errout:
diff --git a/boards/arm/stm32/nucleo-f334r8/src/stm32_spwm.c b/boards/arm/stm32/nucleo-f334r8/src/stm32_spwm.c
index 3cb2d5d246e..0a5c077b5a6 100644
--- a/boards/arm/stm32/nucleo-f334r8/src/stm32_spwm.c
+++ b/boards/arm/stm32/nucleo-f334r8/src/stm32_spwm.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * boards/arm/stm32/nucleo-f334r8/src/stm32_spwm.c
  *
- *   Copyright (C) 2018 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2018, 2019 Gregory Nutt. All rights reserved.
  *   Author: Mateusz Szafoni <raiden00@railab.me>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -1047,7 +1047,7 @@ int spwm_main(int argc, char *argv[])
 
       /* Sleep */
 
-      sleep(1);
+      nxsig_sleep(1);
     }
 
 errout:
diff --git a/boards/arm/stm32/stm32f429i-disco/src/stm32_highpri.c b/boards/arm/stm32/stm32f429i-disco/src/stm32_highpri.c
index 64f2e424714..d92fc0d0095 100644
--- a/boards/arm/stm32/stm32f429i-disco/src/stm32_highpri.c
+++ b/boards/arm/stm32/stm32f429i-disco/src/stm32_highpri.c
@@ -495,7 +495,7 @@ int highpri_main(int argc, char *argv[])
 
       adc1->ad_ops->ao_ioctl(adc1, IO_TRIGGER_REG, 0);
 
-      nxsig_usleep(100);
+      usleep(100);
 #endif
 
 #ifdef HIGHPRI_HAVE_INJECTED
@@ -503,7 +503,7 @@ int highpri_main(int argc, char *argv[])
 
       adc1->ad_ops->ao_ioctl(adc1, IO_TRIGGER_INJ, 0);
 
-      nxsig_usleep(100);
+      usleep(100);
 #endif
       /* Lock global data */
 
@@ -539,7 +539,7 @@ int highpri_main(int argc, char *argv[])
 
       g_highpri.lock = false;
 
-      sleep(1);
+      nxsig_sleep(1);
     }
 
 errout:
diff --git a/drivers/sensors/lsm303agr.c b/drivers/sensors/lsm303agr.c
index 1adeabfe256..6b0b6854cc8 100644
--- a/drivers/sensors/lsm303agr.c
+++ b/drivers/sensors/lsm303agr.c
@@ -10,7 +10,7 @@
  *   Copyright (C) 2016 Omni Hoverboards Inc. All rights reserved.
  *   Author: Paul Alexander Patience <paul-a.patience@polymtl.ca>
  *
- *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2016, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,11 +53,11 @@
 #include <stdlib.h>
 
 #include <nuttx/kmalloc.h>
+#include <nuttx/random.h>
+#include <nuttx/signal.h>
 #include <nuttx/fs/fs.h>
 #include <nuttx/i2c/i2c_master.h>
 #include <nuttx/sensors/lsm303agr.h>
-#include <nuttx/random.h>
-#include <nuttx/signal.h>
 
 #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_LSM303AGR)
 
@@ -834,7 +834,7 @@ static int lsm303agr_selftest(FAR struct lsm303agr_dev_s *priv, uint32_t mode)
       sninfo("\n");
     }
 
-  sleep(2);
+  nxsig_sleep(2);
 
   /* Disable test */
 
diff --git a/drivers/sensors/lsm6dsl.c b/drivers/sensors/lsm6dsl.c
index 6880aa1ef4f..d026bd4fad6 100644
--- a/drivers/sensors/lsm6dsl.c
+++ b/drivers/sensors/lsm6dsl.c
@@ -10,7 +10,7 @@
  *   Copyright (C) 2016 Omni Hoverboards Inc. All rights reserved.
  *   Author: Paul Alexander Patience <paul-a.patience@polymtl.ca>
  *
- *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2016, 2019 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,11 +53,11 @@
 #include <stdlib.h>
 
 #include <nuttx/kmalloc.h>
+#include <nuttx/random.h>
+#include <nuttx/signal.h>
 #include <nuttx/fs/fs.h>
 #include <nuttx/i2c/i2c_master.h>
 #include <nuttx/sensors/lsm6dsl.h>
-#include <nuttx/random.h>
-#include <nuttx/signal.h>
 
 #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_LSM6DSL)
 
@@ -855,7 +855,7 @@ static int lsm6dsl_selftest(FAR struct lsm6dsl_dev_s *priv, uint32_t mode)
       sninfo("\n");
     }
 
-  sleep(2);
+  nxsig_sleep(2);
 
   /* Disable test */
 
diff --git a/drivers/sensors/lsm9ds1.c b/drivers/sensors/lsm9ds1.c
index f60a2fbb41e..5a6761f45da 100644
--- a/drivers/sensors/lsm9ds1.c
+++ b/drivers/sensors/lsm9ds1.c
@@ -47,10 +47,10 @@
 #include <stdlib.h>
 
 #include <nuttx/kmalloc.h>
+#include <nuttx/random.h>
 #include <nuttx/fs/fs.h>
 #include <nuttx/i2c/i2c_master.h>
 #include <nuttx/sensors/lsm9ds1.h>
-#include <nuttx/random.h>
 
 #if defined(CONFIG_I2C) && defined(CONFIG_SENSORS_LSM9DS1)
 
diff --git a/drivers/usbhost/usbhost_max3421e.c b/drivers/usbhost/usbhost_max3421e.c
index 4202e9a5c4f..8d8e0d41338 100644
--- a/drivers/usbhost/usbhost_max3421e.c
+++ b/drivers/usbhost/usbhost_max3421e.c
@@ -3001,7 +3001,7 @@ static int max3421e_connected(FAR struct max3421e_usbhost_s *priv)
   /* Stop SOF generation and reset the bus */
 
   max3421e_busreset(priv);
-  sleep(1);
+  nxsig_sleep(1);
 
   /* Check for low- or full-speed and restart SOF generation. */
 
@@ -3460,7 +3460,7 @@ static int max3421e_getspeed(FAR struct max3421e_usbhost_s *priv,
   /* Stop SOF generation and reset the host port */
 
   max3421e_busreset(priv);
-  sleep(1);
+  nxsig_sleep(1);
 
   /* Get the current device speed */