Real Time Clock 247 May 03, 2004
Philips Semiconductors Preliminary User Manual
LPC2119/2129/2194/2292/2294ARM-based Microcontroller
Clock Control Register (CCR - 0xE0024008)
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 180.
Counter Increment Interrupt
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]).
Alarm Mask
The Alarm Mask Register (AMR) allows the user to mask any of the alarm registers. Table 182 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.
Table 180: Clock Control Register Bits (CCR - 0xE0024008)
CCR Function Description
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.
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.
3:2 CTTEST Test Enable. These bits should always be zero during normal operation.
Table 181: Counter Increment Interrupt Register Bits (CIIR - 0xE002400C)
CIIR Function Description
0 IMSEC When one, an increment of the Second value generates an interrupt.
1 IMMIN When one, an increment of the Minute value generates an interrupt.
2 IMHOUR When one, an increment of the Hour value generates an interrupt.
3 IMDOM When one, an increment of the Day of Month value generates an interrupt.
4 IMDOW When one, an increment of the Day of Week value generates an interrupt.
5 IMDOY When one, an increment of the Day of Year value generates an interrupt.
6 IMMON When one, an increment of the Month value generates an interrupt.
7 IMYEAR When one, an increment of the Year value generates an interrupt.
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