diff --git a/hal/sleep_api.h b/hal/sleep_api.h
index 8747459cb9..aae204f6c6 100644
--- a/hal/sleep_api.h
+++ b/hal/sleep_api.h
@@ -29,32 +29,27 @@ extern "C" {
 
 /** Send the microcontroller to sleep
  *
- * The processor is setup ready for sleep, and sent to sleep using __WFI(). In this mode, the
+ * The processor is setup ready for sleep, and sent to sleep. In this mode, the
  * system clock to the core is stopped until a reset or an interrupt occurs. This eliminates
  * dynamic power used by the processor, memory systems and buses. The processor, peripheral and
  * memory state are maintained, and the peripherals continue to work and can generate interrupts.
  *
  * The processor can be woken up by any internal peripheral interrupt or external pin interrupt.
  *
- * @note
- *  The mbed interface semihosting is disconnected as part of going to sleep, and can not be restored.
- * Flash re-programming and the USB serial port will remain active, but the mbed program will no longer be
- * able to access the LocalFileSystem
+ * The wake-up time shall be less than 10 us.
+ * 
  */
 void hal_sleep(void);
 
 /** Send the microcontroller to deep sleep
  *
  * This processor is setup ready for deep sleep, and sent to sleep using __WFI(). This mode
- * has the same sleep features as sleep plus it powers down peripherals and clocks. All state
- * is still maintained.
+ * has the same sleep features as sleep plus it powers down peripherals and high frequency clocks.
+ * All state is still maintained.
  *
- * The processor can only be woken up by an external interrupt on a pin or a watchdog timer.
+ * The processor can only be woken up by low power ticker, RTC, an external interrupt on a pin or a watchdog timer.
  *
- * @note
- *  The mbed interface semihosting is disconnected as part of going to sleep, and can not be restored.
- * Flash re-programming and the USB serial port will remain active, but the mbed program will no longer be
- * able to access the LocalFileSystem
+ * The wake-up time shall be less than 10 ms.
  */
 void hal_deepsleep(void);
 
diff --git a/targets/TARGET_NXP/TARGET_LPC176X/sleep.c b/targets/TARGET_NXP/TARGET_LPC176X/sleep.c
index c9f6ad4145..22127e0728 100644
--- a/targets/TARGET_NXP/TARGET_LPC176X/sleep.c
+++ b/targets/TARGET_NXP/TARGET_LPC176X/sleep.c
@@ -17,6 +17,13 @@
 #include "cmsis.h"
 #include "mbed_interface.h"
 
+/*
+ * @note
+ *  The mbed interface semihosting is disconnected as part of going to sleep, and can not be restored.
+ * Flash re-programming and the USB serial port will remain active, but the mbed program will no longer be
+ * able to access the LocalFileSystem
+ */
+
 void hal_sleep(void) {
 
 #if (DEVICE_SEMIHOST == 1)