NXP Semiconductors LPC24XX UM10237 - Manual (Page 653)

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User manual Rev. 04 — 26 August 2009 653 of 792
NXP Semiconductors
UM10237
Chapter 26: LPC24XX Real-Time Clock (RTC) and battery RAM
6.2.6 Alarm Mask Register (AMR - 0xE002 4010)
The Alarm Mask Register (AMR) allows the user to mask any of the alarm registers.
Table 26–572 shows the relationship between the bits in the AMR and the alarms. For the
alarm function, every non-masked alarm register must match the corresponding time
counter for an interrupt to be generated. The interrupt is generated only when the counter
comparison first changes from no match to match. The interrupt is removed when a one is
written to the appropriate bit of the Interrupt Location Register (ILR). If all mask bits are
set, then the alarm is disabled.
6.3 Consolidated time registers
The values of the Time Counters can optionally be read in a consolidated format which
allows the programmer to read all time counters with only three read operations. The
various registers are packed into 32 bit values as shown in
Table 26–573 , Table 26–574 ,
and Table 26–575 . The least significant bit of each register is read back at bit 0, 8, 16, or
24.
The Consolidated Time Registers are read only. To write new values to the Time
Counters, the Time Counter addresses should be used.
6.3.1 Consolidated Time Register 0 (CTIME0 - 0xE002 4014)
The Consolidated Time Register 0 contains the low order time values: Seconds, Minutes,
Hours, and Day of Week.
7 SubSecEna Subsecond interrupt enable. NC
0 The sub-second interrupt is disabled.
1 The sub-second interrupt is enabled.
Table 571. Counter Increment Select Mask register (CISS - address 0xE002 4040) bit description
Bit Symbol Value Description Reset
value
Table 572. Alarm Mask Register (AMR - address 0xE002 4010) bit description
Bit Symbol Description Reset
value
0 AMRSEC When 1, the Second value is not compared for the alarm. NA
1 AMRMIN When 1, the Minutes value is not compared for the alarm. NA
2 AMRHOUR When 1, the Hour value is not compared for the alarm. NA
3 AMRDOM When 1, the Day of Month value is not compared for the alarm. NA
4 AMRDOW When 1, the Day of Week value is not compared for the alarm. NA
5 AMRDOY When 1, the Day of Year value is not compared for the alarm. NA
6 AMRMON When 1, the Month value is not compared for the alarm. NA
7 AMRYEAR When 1, the Year value is not compared for the alarm. NA