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UM10601
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2012. All rights reserved.
Preliminary user manual
Rev. 1.0 — 7 November 2012
141 of 313
NXP Semiconductors
UM10601
Chapter 11: LPC800 Multi-Rate Timer (MRT)
11.5.2 One-shot interrupt mode
The one-shot interrupt generates one interrupt after a one-time count. With this mode, you
can generate a single interrupt at any point. This mode can be used to introduce a specific
delay in a software task.
When the timer is in the idle state, writing a non-zero value IVALUE to the INTVALn
register immediately loads the time interval value IVALUE - 1, and the timer starts to count
down. When the timer reaches 0, an interrupt is generated and the timer stops and enters
the idle state.
While the timer is running in the one-shot interrupt mode, you can perform the following
actions:
•
Update the INTVALn register with a new time interval value (>0) and set the LOAD bit
to 1. The timer immediately reloads the new time interval, and starts counting down
from the new value. No interrupt is generated when the TIME_INTVALn register is
updated.
•
Write a 0 to the INTVALn register and set the LOAD bit to 1. The timer immediately
stops counting and moves to the idle state. No interrupt is generated when the
INTVALn register is updated.
11.6 Register description
The reset values shown in
are POR reset values.
Table 134. Register overview: MRT (base address 0x4000 4000)
Name
Access
Address
offset
Description
Reset value
Reference
INTVAL0
R/W
0x0
MRT0 Time interval value register. This value is
loaded into the TIMER0 register.
0
TIMER0
R
0x4
MRT0 Timer register. This register reads the value
of the down-counter.
0x00FF FFFF
CTRL0
R/W
0x8
MRT0 Control register. This register controls the
MRT0 modes.
0
STAT0
R/W
0xC
MRT0 Status register.
0
INTVAL1
R/W
0x10
MRT1 Time interval value register. This value is
loaded into the TIMER1 register.
0
TIMER1
R/W
0x14
MRT1 Timer register. This register reads the value
of the down-counter.
0x00FF FFFF
CTRL1
R/W
0x18
MRT1 Control register. This register controls the
MRT1 modes.
0
STAT1
R/W
0x1C
MRT1 Status register.
0
INTVAL2
R/W
0x20
MRT2 Time interval value register. This value is
loaded into the TIMER2 register.
0
TIMER2
R/W
0x24
MRT2 Timer register. This register reads the value
of the down-counter.
0x00FF FFFF
CTRL2
R/W
0x28
MRT2 Control register. This register controls the
MRT2 modes.
0
STAT2
R/W
0x2C
MRT2 Status register.
0