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UM11029
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User manual
Rev. 1.0 — 16 June 2017
363 of 515
NXP Semiconductors
UM11029
Chapter 20: LPC84x Standard counter/timer (CTIMER)
20.7.1 Interrupt Register
The Interrupt Register consists of 4 bits for the match interrupts and 4 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. Writing a zero has no effect.
20.7.2 Timer Control Register
The Timer Control Register (TCR) is used to control the operation of the Timer/Counter.
20.7.3 Timer Counter register
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 371. Interrupt Register (IR, offset 0x00) 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
31:6
-
Reserved. Read value is undefined, only zero should be written. -
Table 372. Timer Control Register (TCR, offset 0x04) bit description
Bit
Symbol
Value
Description
Reset
value
0
CEN
Counter enable.
0
0
Disabled.The counters are disabled.
1
Enabled. The Timer Counter and Prescale Counter are enabled.
1
CRST
Counter reset.
0
0
Disabled. Do nothing.
1
Enabled. The Timer Counter and the Prescale Counter are synchronously reset on the
next positive edge of the APB bus clock. The counters remain reset until TCR[1] is
returned to zero.
31:2
-
-
Reserved. Read value is undefined, only zero should be written.
-
Table 373. Timer counter register (TC, offset 0x08) bit description
Bit
Symbol
Description
Reset value
31:0
TCVAL
Timer counter value.
0