6.5.7.5 Hibernation (HIB) Module
The HIB module provides logic to switch power off to the main processor and peripherals and to wake on external or time-based events. The HIB module includes power-sequencing logic and has the following features:
- 32-bit RTC with 1/32768-second resolution and a 15-bit subseconds counter
- 32-bit RTC seconds match register and a 15-bit subseconds match for timed wakeup and interrupt generation with 1/32768-second resolution
- RTC predivider trim for making fine adjustments to the clock rate
- Hardware calendar function
- Year, month, day, day of week, hours, minutes, and seconds
- Four-year leap compensation
- 24-hour or AM and PM configuration
- Two mechanisms for power control
- System power control using a discrete external regulator
- On-chip power control using internal switches under register control
- VDD supplies power when valid, even if VBAT > VDD
- Dedicated pin for wake using an external signal
- Can configure the external reset (RST) pin or up to four GPIO port pins as wake sources, with programmable wake level
- Tamper functionality
- Support for four tamper inputs
- Configurable level, weak pullup, and glitch filter
- Configurable tamper event response
- Logging of up to four tamper events
- Optional BBRAM erase on tamper detection
- Tamper detection and wake-from-hibernate capability
- Hibernation clock input failure detect with a switch to the internal oscillator on detection
- RTC operational and hibernation memory valid as long as VDD or VBAT is valid
- Low-battery detection, signaling, and interrupt generation, with optional wake on low battery
- GPIO pin state can be retained during hibernation
- Clock source from an internal low-frequency oscillator (HIB LFIOSC) or a 32.768-kHz external crystal or oscillator
- Sixteen 32-bit words of battery-backed memory to save state during hibernation
- Programmable interrupts for:
- RTC match
- External wake
- Low battery