Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet
Product codes
ATSAM4E-XPRO
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
322
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.
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 1Hz RTC signal, thus taking advantage of a calibrated 1Hz
clock.
clock.
The slow clock source can be fully disabled to reduce power consumption when only an elapsed seconds count is
required.
required.
15.2
Embedded Characteristics
32-bit Free-running Counter on prescaled slow clock or RTC calibrated 1Hz clock
16-bit Configurable Prescaler
Interrupt on Alarm or Counter Increment
15.3
Block Diagram
Figure 15-1.
Real-time Timer
15.4
Functional Description
The programmable 16-bit prescaler value can be configured through the RTPRES field in the
(RTT_MR).
SLCK
RTPRES
RTTINC
ALMS
16-bit
Prescaler
32-bit
Counter
ALMV
=
CRTV
RTT_MR
RTT_VR
RTT_AR
RTT_SR
RTTINCIEN
RTT_MR
0
1
0
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
1
0
RTT_MR
RTC1HZ
RTC 1Hz