UM10503
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User manual
Rev. 1.3 — 6 July 2012
854 of 1269
NXP Semiconductors
UM10503
Chapter 29: LPC43xx Timer0/1/2/3
29.6.1 Timer interrupt registers
The Interrupt Register consists of four bits for the match interrupts and four bits for the
capture interrupts. If an interrupt is generated then the corresponding bit in the IR will be
high. Otherwise, the bit will be low. Writing a logic one to the corresponding IR bit will reset
the interrupt. Writing a zero has no effect. The act of clearing an interrupt for a timer match
also clears any corresponding DMA request.
29.6.2 Timer control registers
The Timer Control Register (TCR) is used to control the operation of the Timer/Counter.
29.6.3 Timer counter registers
The 32-bit Timer Counter register is incremented when the prescale counter reaches its
terminal count. Unless it is reset before reaching its upper limit, the Timer Counter will
count up through the value 0xFFFF FFFF and then wrap back to the value 0x0000 0000.
This event does not cause an interrupt, but a match register can be used to detect an
overflow if needed.
Table 684. Timer interrupt registers (IR - addresses 0x4008 4000 (TIMER0), 0x4008 5000
(TIMER1), 0x400C 3000 (TIMER2), 0x400C 4000 (TIMER3)) bit description
Bit
Symbol
Description
Reset
value
0
MR0INT
Interrupt flag for match channel 0.
0
1
MR1INT
Interrupt flag for match channel 1.
0
2
MR2INT
Interrupt flag for match channel 2.
0
3
MR3INT
Interrupt flag for match channel 3.
0
4
CR0INT
Interrupt flag for capture channel 0 event.
0
5
CR1INT
Interrupt flag for capture channel 1 event.
0
6
CR2INT
Interrupt flag for capture channel 2 event.
0
7
CR3INT
Interrupt flag for capture channel 3 event.
0
31:8
-
Reserved.
-
Table 685. Timer control register (TCR - addresses 0x4008 4004 (TIMER0), 0x4008 5004
(TIMER1), 0x400C 3004 (TIMER2), 0x400C 4004 (TIMER3)) bit description
Bit
Symbol
Description
Reset value
0
CEN
When one, the Timer Counter and Prescale Counter are
enabled for counting. When zero, the counters are
disabled.
0
1
CRST
When one, the Timer Counter and the Prescale Counter
are synchronously reset on the next positive edge of
PCLK. The counters remain reset until TCR[1] is
returned to zero.
0
31:2
-
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
NA