Datasheet

Real Time Clock (RTC)
Intel
®
Quark™ microcontroller D2000
January 2016 Datasheet
Document Number: 333577-002EN 371
20.2.1 RTC Clock
The RTC clock is the output of a 4bit prescaler (see Clocking Section) that is driven by
the output of the 32.768 kHz Crystal Oscillator.
This allows a range of clock frequencies to be generated as shown in the table below:
Table 50. RTC Clock Scaling
Scaling factor
Output Clock Frequency
0
32.768 kHz
1
16.384 kHz
2
8.192 kHz
3
4.096 kHz
4
2.048 kHz
5
1.024 kHz
6
512 Hz
7
256 Hz
8
128 Hz
9
64 Hz
10
32 Hz
11
16 Hz
12
8 Hz
13
4 Hz
14
2 Hz
15
1 Hz
20.2.2 Counter Functionality
The RTC contains a single 32bit up-counter, the counter starts to increment when the
RTC is taken out of reset. The counter increments on successive edges of the RTC
clock.
The counter Start Value is loaded by writing a 32bit value to the Counter Load
Register. The Counter supports loading a Start Value while it is incrementing.
When the counter reaches its max value (2
32
-1) it wraps to 0 and continues
incrementing.
The RTC supports reading the Counter via the read-only Counter Value Register.