28.5.1 Real-time Timer Mode Register

Name: RTT_MR
Offset: 0x00
Reset: 0x00008000
Property: Read/Write

Bit 3130292827262524 
        RTC1HZ 
Access R/W 
Reset 0 
Bit 2322212019181716 
    RTTDIS RTTRSTRTTINCIENALMIEN 
Access R/WR/WR/WR/W 
Reset 0000 
Bit 15141312111098 
 RTPRES[15:8] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 10000000 
Bit 76543210 
 RTPRES[7:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bit 24 – RTC1HZ Real-Time Clock 1Hz Clock Selection

ValueDescription
0 The RTT 32-bit counter is driven by the 16-bit prescaler roll-over events.
1 The RTT 32-bit counter is driven by the 1Hz RTC clock.

Bit 20 – RTTDIS Real-time Timer Disable

ValueDescription
0 The RTT is enabled.
1 The RTT is disabled (no dynamic power consumption).

Bit 18 – RTTRST Real-time Timer Restart

ValueDescription
0

No effect.

1

Reloads and restarts the clock divider with the new programmed value. This also resets the 32-bit counter.

Bit 17 – RTTINCIEN Real-time Timer Increment Interrupt Enable

ValueDescription
0

The bit RTTINC in RTT_SR has no effect on interrupt.

1

The bit RTTINC in RTT_SR asserts interrupt.

Bit 16 – ALMIEN Alarm Interrupt Enable

ValueDescription
0

The bit ALMS in RTT_SR has no effect on interrupt.

1

The bit ALMS in RTT_SR asserts interrupt.

Bits 15:0 – RTPRES[15:0] Real-time Timer Prescaler Value

Defines the number of SLCK periods required to increment the RTT. The RTTINCIEN bit must be cleared prior to writing a new RTPRES value.

RTPRES is defined as follows:

  • RTPRES = 0: The prescaler period is equal to 216 * SLCK periods.
  • RTPRES = 1 or 2: forbidden.
  • RTPRES ≠ 0,1 or 2: The prescaler period is equal to RTPRES * SLCK periods.