Datasheet

278
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
15. Real-time Timer (RTT)
15.1 Description
The Real-time Timer (RTT) is built around a 32-bit counter used to count roll-over events of the programmable 16-bit
prescaler driven from the 32 kHz slow clock source. It generates a periodic interrupt and/or triggers an alarm on a
programmed value.
The RTT can also be configured to be driven by the RTC 1 Hz signal, thus taking advantage of a calibrated 1 Hz clock.
The slow clock source can be fully disabled to reduce power consumption when only an elapsed seconds count is
required.
15.2 Embedded Characteristics
 32-bit Free-running Counter on prescaled slow clock or RTC calibrated 1 Hz clock
 16-bit Configurable Prescaler
 Interrupt on Alarm
15.3 Block Diagram
Figure 15-1. Real-time Timer
SLCK
RTPRES
RTTINC
ALMS
16-bit
Prescaler
32-bit
Counter
ALMV
=
CRTV
RTT_MR
RTT_VR
RTT_AR
RTT_SR
RTTINCIEN
RTT_MR
0
10
ALMIEN
rtt_int
RTT_MR
set
set
RTT_SR
read
RTT_SR
reset
reset
RTT_MR
reload
rtt_alarm
RTTRST
RTT_MR
RTTRST
RTT_MR
RTTDIS
10
RTT_MR
RTC1HZ
RTC 1Hz