Datasheet

C161S
Functional Description
Data Sheet 21 V1.0, 2003-11
3.5 Real Time Clock
The Real Time Clock (RTC) module of the C161S consists of a chain of 3 divider blocks,
a fixed 8:1 divider, the reloadable 16-bit timer T14, and the 32-bit RTC timer (accessible
via registers RTCH and RTCL). The RTC module is directly clocked with the on-chip
oscillator frequency divided by 32 via a separate clock driver (
f
RTC
= f
OSC
/32) and is
therefore independent from the selected clock generation mode of the C161S. All timers
count up.
The RTC module can be used for different purposes:
• System clock to determine the current time and date
• Cyclic time based interrupt
• 48-bit timer for long term measurements
Figure 7 RTC Block Diagram
Note: The registers associated with the RTC are not affected by a reset in order to
maintain the correct system time even when intermediate resets are executed.
MCD04432
T14REL
T14 8:1
RTC
f
RTCLRTCH
Interrupt
Request
Reload