
DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
536 of 808
NXP Semiconductors
UM10360
Chapter 27: LPC17xx Real-Time Clock (RTC) and backup registers
6.2 Miscellaneous register group
6.2.1 Interrupt Location Register (ILR - 0x4002 4000)
The Interrupt Location Register is a 2-bit register that specifies which blocks are
generating an interrupt (see
). Writing a one to the appropriate bit clears the
corresponding interrupt. Writing a zero has no effect. This allows the programmer to read
this register and write back the same value to clear only the interrupt that is detected by
the read.
6.2.2 Clock Control Register (CCR - 0x4002 4008)
The clock register is a 4-bit register that controls the operation of the clock divide circuit.
Each bit of the clock register is described in
.
Table 490. Interrupt Location Register (ILR - address 0x4002 4000) bit description
Bit
Symbol
Description
Reset
value
0
RTCCIF
When one, the Counter Increment Interrupt block generated an interrupt.
Writing a one to this bit location clears the counter increment interrupt.
0
1
RTCALF
When one, the alarm registers generated an interrupt. Writing a one to
this bit location clears the alarm interrupt.
0
7:1
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
Table 491. Clock Control Register (CCR - address 0x4002 4008) bit description
Bit
Symbol
Value
Description
Reset
value
0
CLKEN
Clock Enable.
NC
1
The time counters are enabled.
0
The time counters are disabled so that they may be
initialized.
1
CTCRST
CTC Reset.
0
1
When one, the elements in the Clock Tick Counter are reset.
The elements remain reset until CCR[1] is changed to zero.
0
No effect.
3:2
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
4
CCALEN
Calibration counter enable.
NC
1
The calibration counter is disabled and reset to zero.
0
The calibration counter is enabled and counting, using the
1 Hz clock. When the calibration counter is equal to the
value of the CALIBRATION register, the counter resets and
repeats counting up to the value of the CALIBRATION
register. See
7:5
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA