The Real-time counter (RTC) module provides a generic, low power timer on the low-frequency clock source (LFCLK).
The RTC module features a 24-bit COUNTER, a 12-bit (1/X) prescaler, capture/compare registers, and a tick event generator for low power, tickless RTOS implementation.
The RTC runs off the LFCLK.
The COUNTER resolution is 30.517 µs. Depending on the source, the RTC is able to run while the HFCLK is OFF and PCLK16M is not available.
The software has to explicitly start LFCLK before using the RTC.
See CLOCK — Clock control for more information about clock sources.
Counter increment frequency:
fRTC [kHz] = 32.768 / (PRESCALER + 1 )
The PRESCALER register is read/write when the RTC is stopped. The PRESCALER register is read-only once the RTC is STARTed. Writing to the PRESCALER register when the RTC is started has no effect.
The PRESCALER is restarted on START, CLEAR, and TRIGOVRFLW, meaning the prescaler value is latched to an internal register (<<PRESC>>) on these tasks.
Examples of different frequency configurations are as following:
Desired COUNTER frequency 100 Hz (10 ms counter period)
PRESCALER = round(32.768 kHz / 100 Hz) - 1 = 327
fRTC = 99.9 Hz
10009.576 μs counter period
Desired COUNTER frequency 8 Hz (125 ms counter period)
PRESCALER = round(32.768 kHz / 8 Hz) – 1 = 4095
fRTC = 8 Hz
125 ms counter period
Prescaler | Counter resolution | Overflow |
---|---|---|
0 | 30.517 μs | 512 seconds |
28-1 | 7812.5 μs | 131072 seconds |
212-1 | 125 ms | 582.542 hours |
The COUNTER increments on LFCLK when the internal PRESCALER register (<<PRESC>>) is 0x00. <<PRESC>> is reloaded from the PRESCALER register. If enabled, the TICK event occurs on each increment of the COUNTER. The TICK event is disabled by default.
The TRIGOVRFLW task sets the COUNTER value to 0xFFFFF0 to allow SW test of the overflow condition.
OVRFLW occurs when COUNTER overflows from 0xFFFFFF to 0.
The TICK event enables low power tickless RTOS implementation as it optionally provides a regular interrupt source for a RTOS without the need to use the ARM® SysTick feature.
Using the RTC TICK event rather than the SysTick allows the CPU to be powered down while still keeping RTOS scheduling active.
To optimize RTC power consumption, events in the RTC can be individually disabled to prevent PCLK16M and HFCLK being requested when those events are triggered. This is managed using the EVTEN register.
For example, if the TICK event is not required for an application, this event should be disabled as it is frequently occurring and may increase power consumption if HFCLK otherwise could be powered down for long durations.
This means that the RTC implements a slightly different task and event system compared to the standard system described in Peripheral interface. The RTC task and event system is illustrated in Tasks, events, and interrupts in the RTC.
There are a number of Compare registers.
For more information, see Registers.
When setting a compare register, the following behavior of the RTC compare event should be noted:
If the COUNTER is N and the current CC register value is N+1 or N+2 when a new CC value is written, a match may trigger on the previous CC value before the new value takes effect. If the current CC value is greater than N+2 when the new value is written, there will be no event due to the old value.
Jitter or delay in the RTC is due to the peripheral clock being a low frequency clock (LFCLK) which is not synchronous to the faster PCLK16M.
Registers in the peripheral interface, part of the PCLK16M domain, have a set of mirrored registers in the LFCLK domain. For example, the COUNTER value accessible from the CPU is in the PCLK16M domain and is latched on read from an internal register called COUNTER in the LFCLK domain. COUNTER is the register which is actually modified each time the RTC ticks. These registers must be synchronised between clock domains (PCLK16M and LFCLK).
The following is a summary of the jitter introduced on tasks and events.
Task | Delay |
---|---|
CLEAR, STOP, START, TRIGOVRFLOW | +15 to 46 μs |
Operation/Function | Jitter |
---|---|
START to COUNTER increment | +/- 15 μs |
COMPARE to COMPARE 1 | +/- 62.5 ns |
To read the COUNTER register, the internal <<COUNTER>> value is sampled.
To ensure that the <<COUNTER>> is safely sampled (considering an LFCLK transition may occur during a read), the CPU and core memory bus are halted for three cycles by lowering the core PREADY signal. The Read takes the CPU 2 cycles in addition resulting in the COUNTER register read taking a fixed five PCLK16M clock cycles.
Base address | Peripheral | Instance | Description | Configuration | |
---|---|---|---|---|---|
0x4000B000 | RTC | RTC0 |
Real-time counter 0 |
CC[0..2] implemented, CC[3] not implemented |
|
0x40011000 | RTC | RTC1 |
Real-time counter 1 |
CC[0..3] implemented |
|
0x40024000 | RTC | RTC2 |
Real-time counter 2 |
CC[0..3] implemented |
Register | Offset | Description | |
---|---|---|---|
TASKS_START | 0x000 |
Start RTC COUNTER |
|
TASKS_STOP | 0x004 |
Stop RTC COUNTER |
|
TASKS_CLEAR | 0x008 |
Clear RTC COUNTER |
|
TASKS_TRIGOVRFLW | 0x00C |
Set COUNTER to 0xFFFFF0 |
|
EVENTS_TICK | 0x100 |
Event on COUNTER increment |
|
EVENTS_OVRFLW | 0x104 |
Event on COUNTER overflow |
|
EVENTS_COMPARE[0] | 0x140 |
Compare event on CC[0] match |
|
EVENTS_COMPARE[1] | 0x144 |
Compare event on CC[1] match |
|
EVENTS_COMPARE[2] | 0x148 |
Compare event on CC[2] match |
|
EVENTS_COMPARE[3] | 0x14C |
Compare event on CC[3] match |
|
INTENSET | 0x304 |
Enable interrupt |
|
INTENCLR | 0x308 |
Disable interrupt |
|
EVTEN | 0x340 |
Enable or disable event routing |
|
EVTENSET | 0x344 |
Enable event routing |
|
EVTENCLR | 0x348 |
Disable event routing |
|
COUNTER | 0x504 |
Current COUNTER value |
|
PRESCALER | 0x508 |
12 bit prescaler for COUNTER frequency (32768/(PRESCALER+1)). Must be written when RTC is stopped. |
|
CC[0] | 0x540 |
Compare register 0 |
|
CC[1] | 0x544 |
Compare register 1 |
|
CC[2] | 0x548 |
Compare register 2 |
|
CC[3] | 0x54C |
Compare register 3 |
Address offset: 0x000
Start RTC COUNTER
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | W |
TASKS_START |
Start RTC COUNTER |
||||||||||||||||||||||||||||||||
Trigger |
1 |
Trigger task |
Address offset: 0x004
Stop RTC COUNTER
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | W |
TASKS_STOP |
Stop RTC COUNTER |
||||||||||||||||||||||||||||||||
Trigger |
1 |
Trigger task |
Address offset: 0x008
Clear RTC COUNTER
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | W |
TASKS_CLEAR |
Clear RTC COUNTER |
||||||||||||||||||||||||||||||||
Trigger |
1 |
Trigger task |
Address offset: 0x00C
Set COUNTER to 0xFFFFF0
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | W |
TASKS_TRIGOVRFLW |
Set COUNTER to 0xFFFFF0 |
||||||||||||||||||||||||||||||||
Trigger |
1 |
Trigger task |
Address offset: 0x100
Event on COUNTER increment
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
EVENTS_TICK |
Event on COUNTER increment |
||||||||||||||||||||||||||||||||
NotGenerated |
0 |
Event not generated |
|||||||||||||||||||||||||||||||||
Generated |
1 |
Event generated |
Address offset: 0x104
Event on COUNTER overflow
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
EVENTS_OVRFLW |
Event on COUNTER overflow |
||||||||||||||||||||||||||||||||
NotGenerated |
0 |
Event not generated |
|||||||||||||||||||||||||||||||||
Generated |
1 |
Event generated |
Address offset: 0x140 + (n × 0x4)
Compare event on CC[n] match
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | ||||||||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
EVENTS_COMPARE |
Compare event on CC[n] match |
||||||||||||||||||||||||||||||||
NotGenerated |
0 |
Event not generated |
|||||||||||||||||||||||||||||||||
Generated |
1 |
Event generated |
Address offset: 0x304
Enable interrupt
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | F | E | D | C | B | A | |||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
TICK |
Write '1' to enable interrupt for event TICK |
||||||||||||||||||||||||||||||||
Set |
1 |
Enable |
|||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
B | RW |
OVRFLW |
Write '1' to enable interrupt for event OVRFLW |
||||||||||||||||||||||||||||||||
Set |
1 |
Enable |
|||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
C-F | RW |
COMPARE[i] (i=0..3) |
Write '1' to enable interrupt for event COMPARE[i] |
||||||||||||||||||||||||||||||||
Set |
1 |
Enable |
|||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
Address offset: 0x308
Disable interrupt
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | F | E | D | C | B | A | |||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
TICK |
Write '1' to disable interrupt for event TICK |
||||||||||||||||||||||||||||||||
Clear |
1 |
Disable |
|||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
B | RW |
OVRFLW |
Write '1' to disable interrupt for event OVRFLW |
||||||||||||||||||||||||||||||||
Clear |
1 |
Disable |
|||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
C-F | RW |
COMPARE[i] (i=0..3) |
Write '1' to disable interrupt for event COMPARE[i] |
||||||||||||||||||||||||||||||||
Clear |
1 |
Disable |
|||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
Address offset: 0x340
Enable or disable event routing
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | F | E | D | C | B | A | |||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
TICK |
Enable or disable event routing for event TICK |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Disable |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Disable |
|||||||||||||||||||||||||||||||||
B | RW |
OVRFLW |
Enable or disable event routing for event OVRFLW |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Disable |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Disable |
|||||||||||||||||||||||||||||||||
C-F | RW |
COMPARE[i] (i=0..3) |
Enable or disable event routing for event COMPARE[i] |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Disable |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Disable |
Address offset: 0x344
Enable event routing
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | F | E | D | C | B | A | |||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
TICK |
Write '1' to enable event routing for event TICK |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
Set |
1 |
Enable |
|||||||||||||||||||||||||||||||||
B | RW |
OVRFLW |
Write '1' to enable event routing for event OVRFLW |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
Set |
1 |
Enable |
|||||||||||||||||||||||||||||||||
C-F | RW |
COMPARE[i] (i=0..3) |
Write '1' to enable event routing for event COMPARE[i] |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
Set |
1 |
Enable |
Address offset: 0x348
Disable event routing
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | F | E | D | C | B | A | |||||||||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
TICK |
Write '1' to disable event routing for event TICK |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
Clear |
1 |
Disable |
|||||||||||||||||||||||||||||||||
B | RW |
OVRFLW |
Write '1' to disable event routing for event OVRFLW |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
Clear |
1 |
Disable |
|||||||||||||||||||||||||||||||||
C-F | RW |
COMPARE[i] (i=0..3) |
Write '1' to disable event routing for event COMPARE[i] |
||||||||||||||||||||||||||||||||
Disabled |
0 |
Read: Disabled |
|||||||||||||||||||||||||||||||||
Enabled |
1 |
Read: Enabled |
|||||||||||||||||||||||||||||||||
Clear |
1 |
Disable |
Address offset: 0x504
Current COUNTER value
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | R |
COUNTER |
Counter value |
Address offset: 0x508
12 bit prescaler for COUNTER frequency (32768/(PRESCALER+1)). Must be written when RTC is stopped.
Bit number | 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 | |||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ID | A | A | A | A | A | A | A | A | A | A | A | A | |||||||||||||||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
PRESCALER |
Prescaler value |
Address offset: 0x540 + (n × 0x4)
Compare register n
Bit number | 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 | |||
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ID | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |||||||||||
Reset 0x00000000 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |||
ID | Access | Field | Value ID | Value | Description | ||||||||||||||||||||||||||||||
A | RW |
COMPARE |
Compare value |