UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
148 of 362
NXP Semiconductors
UM10208
Chapter 13: LPC2800 RTC
6.1.3 Clock Tick Counter Register (CTCR - 0x8000 2004)
The Clock Tick Counter is read only. It can be reset to zero through the Clock Control
Register (CCR). The CTC consists of the bits of the clock divider counter.
6.1.4 Clock Control Register (CCR - 0x8000 2008)
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
.
6.1.5 Counter Increment Interrupt Register (CIIR - 0x8000 200C)
The Counter Increment Interrupt Register (CIIR) gives the ability to generate an interrupt
every time a counter is incremented. This interrupt remains valid until cleared by writing a
one to bit zero of the Interrupt Location Register (ILR[0]).
Table 154. Interrupt Location Register (ILR - address 0x8000 2000)
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.
NC
1
RTCALF
When one, the alarm registers generated an interrupt. Writing a one to
this bit location clears the alarm interrupt.
NC
31:2
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
Table 155. Clock Tick Counter Register (CTCR - address 0x8000 2004)
Bit
Symbol
Description
Reset
value
14:0
Clock Tick
Counter
Prior to the Seconds counter, the CTC counts 32,768 clocks per
second.
NA
31:15
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
Table 156. Clock Control Register (CCR - address 0x8000 2008)
Bit
Symbol
Description
Reset
value
0
CLKEN
Clock Enable. When this bit is a one the time counters are enabled.
When it is a zero, they are disabled so that they may be initialized.
NA
1
CTCRST
CTC Reset. When one, the elements in the Clock Tick Counter are
reset. The elements remain reset until CCR[1] is changed to zero.
NA
3:2
CTTEST
Test Enable. These bits should always be zero during normal
operation.
NA
31:4
-
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
Table 157. Counter Increment Interrupt Register (CIIR - address 0x8000 200C)
Bit
Symbol
Description
Reset
value
0
IMSEC
When 1, an increment of the Second value generates an interrupt.
NA
1
IMMIN
When 1, an increment of the Minute value generates an interrupt.
NA
2
IMHOUR
When 1, an increment of the Hour value generates an interrupt.
NA