NXP Semiconductors LPC24XX UM10237, User Manual, Page: 649 / 792

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User manual Rev. 02 — 19 December 2008 649 of 792
NXP Semiconductors
UM10237
Chapter 26: LPC24XX Real-Time Clock (RTC) and battery RAM
6. Register description
The RTC includes a number of registers. The address space is split into four sections by
functionality. The first eight addresses are the Miscellaneous Register Group
(
Section 26–6.2 ). The second set of eight locations are the Time Counter Group
( Section 26–6.4 ). The third set of eight locations contain the Alarm Register Group
( Section 26–7 ). The remaining registers control the Reference Clock Divider.
The Real Time Clock includes the register shown in Table 26–566 . Detailed descriptions
of the registers follow. In these descriptions, for most of the registers the Reset Value
column shows "NC", meaning that these registers are not changed by a Reset. Software
must initialize these registers between power-on and setting the RTC into operation.
Table 566. Summary of Real-Time Clock registers
Name Size Description Access Reset
Value
[1]
Address
ILR 2 Interrupt Location Register R/W NC 0xE002 4000
CTC 15 Clock Tick Counter RO NC 0xE002 4004
CCR 4 Clock Control Register R/W NC 0xE002 4008
CIIR 8 Counter Increment Interrupt Register R/W NC 0xE002 400C
AMR 8 Alarm Mask Register R/W NC 0xE002 4010
CTIME0 32 Consolidated Time Register 0 RO NC 0xE002 4014
CTIME1 32 Consolidated Time Register 1 RO NC 0xE002 4018
CTIME2 32 Consolidated Time Register 2 RO NC 0xE002 401C
SEC 6 Seconds Counter R/W NC 0xE002 4020
MIN 6 Minutes Register R/W NC 0xE002 4024
HOUR 5 Hours Register R/W NC 0xE002 4028
DOM 5 Day of Month Register R/W NC 0xE002 402C
DOW 3 Day of Week Register R/W NC 0xE002 4030
DOY 9 Day of Year Register R/W NC 0xE002 4034
MONTH 4 Months Register R/W NC 0xE002 4038
YEAR 12 Years Register R/W NC 0xE002 403C
CISS 8 Counter Increment select mask for
Sub-Second interrupt R/W NC 0xE002 4040
ALSEC 6 Alarm value for Seconds R/W NC 0xE002 4060
ALMIN 6 Alarm value for Minutes R/W NC 0xE002 4064
ALHOUR 5 Alarm value for Seconds R/W NC 0xE002 4068
ALDOM 5 Alarm value for Day of Month R/W NC 0xE002 406C
ALDOW 3 Alarm value for Day of Week R/W NC 0xE002 4070
ALDOY 9 Alarm value for Day of Year R/W NC 0xE002 4074
ALMON 4 Alarm value for Months R/W NC 0xE002 4078
ALYEAR 12 Alarm value for Year R/W NC 0xE002 407C
PREINT 13 Prescaler value, integer portion R/W 0 0xE002 4080
PREFRAC 15 Prescaler value, fractional portion R/W 0 0xE002 4084