13. RTCC - Real Time Counter and Calendar
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Quick Facts
What?
The Real Time Counter and Calendar (RTCC) is a
32-bit counter ensuring timekeeping in low energy
modes. The RTCC also includes a calendar mode
for easy time and date keeping. In addition, the
RTCC includes 128 bytes of general purpose reten-
tion data, allowing persistent data storage in all en-
ergy modes except EM4 Shutoff.
Why?
Timekeeping over long time periods while using as
little power as possible is required in many low pow-
er applications.
How?
A low frequency oscillator is used as clock signal
and the RTCC has three different Capture/Compare
channels which can trigger wake-up, generate PRS
signalling, or capture system events. 32-bit resolu-
tion and selectable prescaling allow the system to
stay in low energy modes for long periods of time
and still maintain reliable timekeeping.
13.1 Introduction
The Real Time Counter and Calendar (RTCC) contains a 32-bit counter/calendar in combination with a 15-bit pre-counter to allow flexi-
ble prescaling of the main counter. The RTCC is available in all energy modes except EM4 Shutoff.
Three individually configurable Capture/Compare channels are available in the RTCC. These can be used to trigger interrupts, generate
PRS signals, capture system events, and to wake the device up from a low energy mode. The RTCC also includes 128 bytes of general
purpose storage and a Binary Coded Decimal (BCD) calendar mode, enabling easy time and date keeping.
13.2 Features
• 32-bit Real Time Counter.
• 15-bit pre-counter, for flexible frequency scaling or for use as an independent counter.
• EM4 Hibernate operation and wakeup.
• 128 byte general purpose retention data.
• Oscillator failure detection.
• Can continue through system reset; only reset by power loss, pin, or software reset.
• Calendar mode.
• BCD encoding.
• Three programmable alarms.
• Leap year correction.
• Three Capture/Compare registers.
• Capture of PRS events from other parts of the system.
• Compare match or input capture can trigger interrupts.
• Compare register 1, RTCC_CC1_CCV can be used as a top value for the main counter.
• Compare register 0, RTCC_CC0_CCV can be used as a top value for the pre-counter.
• Compare match events are available to other peripherals through the Peripheral Reflex System (PRS).
Reference Manual
RTCC - Real Time Counter and Calendar
silabs.com
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