From the application processor (the ARM Cortex-M4 processor and its peripherals) standpoint, the
following power modes are supported:
- Active mode:
- The processor is clocked at 80 MHz.
- The required set of peripherals are running at configured clock rates.
- Sleep mode:
- The processor is clock-gated until an interrupt event.
- Reduces consumption by 3 mA with respect to active mode.
- Immediate wakeup.
- The required set of peripherals is running at preconfigured clock rates.
- By default, the sleep clock to the peripherals is disabled. If the application chooses to
enter sleep anytime and requires certain peripherals to be active, the sleep clock to the peripheral must be enabled in advance (see
Section 15.6 and Section 15.3).
- Low-power deep-sleep mode (LPDS):
- Up to 256KB of SRAM retention. No logic retention.
- TI SW API and framework provided for transparent save and restore of processor
context, peripheral, and pin configurations
- Total system current (including Wi-Fi and network periodic wakeup) is as low as 700
µA.
- When networking and Wi-Fi subsystems are disabled, the chip draws approximately 120 µA.
- 40-MHz crystal and PLL are turned off. 32.768-kHz crystal is kept alive.
- Most digital logic is turned off. Digital supply voltage is reduced to 0.9 V.
- SRAM can be retained in multiples of 64KB.
- Processor and peripheral registers are not retained. Global always-ON configurations at
SoC level are retained.
- Configurable wake-on-pad (one of six pads).
- Less that 5-ms wake-up latency.
- Recommended for ultra-low power, always-connected cloud, and Wi-Fi applications.
- Hibernate mode (HIB):
- 32.768-kHz crystal is kept alive.
- Wake on RTC (for example, the 32-kHz slow clock counter) or selected GPIO.
- No SRAM or logic retention.
- 2 × 32-bit general-purpose retention registers.
- These registers are powered by the input supply directly, and retain their content as
long as the chip is not reset (nRESET=1) and the supply stays above the blackout level (1.4 V).
- Ultra-low current of 4 µA, including RTC.
- Less than 10-ms wake-up latency.
- Recommended for ultra-low power, infrequently connected cloud, and Wi-Fi
applications.
- A brief hibernation may also be used by software to implement a full system reboot as
part of an over-the-air (OTA) software upgrade, or to restore the system to a ensured clean state following a watchdog reset.
- Once a brownout condition is detected, the application software may choose to enter
hibernate mode to prevent further oscillatory brownouts that may cause unpredictable system behavior and possible damage to the end
equipment. The system can subsequently be made to restart on an RTC timer, on a chip reset, or on plugging of new batteries.
- Shutdown mode:
- 32.768-kHz is in off mode
- Complete wake from cold boot
- Very low leakage current of approximately 1 µA
- Recommended to be used when radio activity is low and the device can be in off mode in
between
For CC32xx applications where battery life is critical, maximize the fraction of time spent in
LPDS or HIB modes compared to active mode and other sleep modes.