1. Introduction

Sleep modes in general are ways to reduce power when there are no radio activity, when the BLE (Bluetooth Low Energy) core and the radio can be turned off. Apart from controlling the power status of the BLE core and the radio, the DA14531 offers the ability to control the state of the power domains except for AON (Always ON) domain. This will be explained in the coming chapters.

This document will give an overview on how to configure DA14531 SoC (System on Chip) in one of the three available sleep modes, namely,

  • Extended sleep mode (with or without OTP copy)
  • Deep sleep mode (also known as shipping clocked mode)
  • Hibernation mode (also known as shipping clock-less mode)

Depending on the end application, the user can opt for one of the power saving sleep modes:

  • Extended sleep :
    • In case of extended sleep, the power consumption is more compared to deep sleep or hibernation mode. The reason being, the sleep power domain and always powered On domain, are active and the RAM is retained.
    • Since it is running from SysRAM, the time from wake-up to advertisement is shorter however this is a trade-off as the sleep current is higher.
    • The power numbers are mentioned in this document in later chapters to get an overview.
  • Deep sleep:
    • It’s also called shipping clocked mode. By default no retention memory is retained which leads to lower power consumption. However, the sleep power domain and powered On domain are On.
    • Since no RAM is retained, the code must be burnt in the OTP and run from OTP. The wake-up takes a longer time compared to when the device is in extended sleep as during the booting the code is copied from OTP to SysRAM and then executed. But the advantage over-time is that the average sleep current is less compared to extended sleep current.
    • Running from OTP consumes more power as compared to running it from SysRAM, but that is the trade-off.
  • Hibernation mode:
    • It’s also called shipping clock-less mode (NO clocks running). RAM may or may not be retained but the sleep power domain (PD_SLP) is powered off. This leads to the sleep current value less than deep sleep mode.
    • The wake-up from hibernation is possible by programming a GPIO (P0_1, P0_2, …, P0_5) to wake the device up.
    • This mode is particularly useful in applications where the device for much of its life-time is in sleep.

More details on each of the modes and configurations is explained in coming chapters.

Later in the document there will be a display of the power measurement numbers for the three modes using DA145xxDEVKT-P PRO-Motherboard.