SAM3XA RTT

Real-time Timer (RTT) User Interface

Registers

Register Mapping

Address	Register	Name	Access	Reset
0x400E1A30	Mode Register	RTT_MR	read-write	0x00008000
0x400E1A34	Alarm Register	RTT_AR	read-write	0xFFFFFFFF
0x400E1A38	Value Register	RTT_VR	read-only	0x00000000
0x400E1A3C	Status Register	RTT_SR	read-only	0x00000000

Register Fields

RTT Mode Register

Name: RTT_MR

Access: read-write

Address: 0x400E1A30

31	30	29	28	27	26	25	24
-	-	-	-	-	-	-	-
23	22	21	20	19	18	17	16
-	-	-	-	-	RTTRST	RTTINCIEN	ALMIEN
15	14	13	12	11	10	9	8
RTPRES
7	6	5	4	3	2	1	0
RTPRES

• RTPRES: Real-time Timer Prescaler Value

-

• ALMIEN: Alarm Interrupt Enable

  Value	Name	Description
  0	-	The bit ALMS in RTT_SR has no effect on interrupt.
  1	-	The bit ALMS in RTT_SR asserts interrupt.

• RTTINCIEN: Real-time Timer Increment Interrupt Enable

  Value	Name	Description
  0	-	The bit RTTINC in RTT_SR has no effect on interrupt.
  1	-	The bit RTTINC in RTT_SR asserts interrupt.

• RTTRST: Real-time Timer Restart

  Value	Name	Description
  0	-	No effect.
  1	-	Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.

RTT Alarm Register

Name: RTT_AR

Access: read-write

Address: 0x400E1A34

31	30	29	28	27	26	25	24
ALMV
23	22	21	20	19	18	17	16
ALMV
15	14	13	12	11	10	9	8
ALMV
7	6	5	4	3	2	1	0
ALMV

• ALMV: Alarm Value

-

RTT Value Register

Name: RTT_VR

Access: read-only

Address: 0x400E1A38

31	30	29	28	27	26	25	24
CRTV
23	22	21	20	19	18	17	16
CRTV
15	14	13	12	11	10	9	8
CRTV
7	6	5	4	3	2	1	0
CRTV

• CRTV: Current Real-time Value

-

RTT Status Register

Name: RTT_SR

Access: read-only

Address: 0x400E1A3C

31	30	29	28	27	26	25	24
-	-	-	-	-	-	-	-
23	22	21	20	19	18	17	16
-	-	-	-	-	-	-	-
15	14	13	12	11	10	9	8
-	-	-	-	-	-	-	-
7	6	5	4	3	2	1	0
-	-	-	-	-	-	RTTINC	ALMS

• ALMS: Real-time Alarm Status

  Value	Name	Description
  0	-	The Real-time Alarm has not occurred since the last read of RTT_SR.
  1	-	The Real-time Alarm occurred since the last read of RTT_SR.

• RTTINC: Real-time Timer Increment

  Value	Name	Description
  0	-	The Real-time Timer has not been incremented since the last read of the RTT_SR.
  1	-	The Real-time Timer has been incremented since the last read of the RTT_SR.