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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
488 of 808
NXP Semiconductors
UM10360
Chapter 24: LPC17xx Pulse Width Modulator (PWM)
7.2 PWM Timer Control Register (PWM1TCR 0x4001 8004)
The PWM Timer Control Register (PWMTCR) is used to control the operation of the PWM
Timer Counter. The function of each of the bits is shown in
7.3 PWM Count Control Register (PWM1CTCR - 0x4001 8070)
The Count Control Register (CTCR) is used to select between Timer and Counter mode,
and in Counter mode to select the pin and edge(s) for counting. The function of each of
the bits is shown in
.
4
PWMCAP0
Interrupt
Interrupt flag for capture input 0
0
5
PWMCAP1
Interrupt
Interrupt flag for capture input 1.
0
7:6
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
8
PWMMR4 Interrupt Interrupt flag for PWM match channel 4.
0
9
PWMMR5 Interrupt Interrupt flag for PWM match channel 5.
0
10
PWMMR6 Interrupt Interrupt flag for PWM match channel 6.
0
15:11 -
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
Table 428: PWM Interrupt Register (PWM1IR - address 0x4001 8000) bit description
Bit
Symbol
Description
Reset
Value
Table 429: PWM Timer Control Register (PWM1TCR address 0x4001
8
004) bit description
Bit
Symbol
Value
Description
Reset
Value
0
Counter Enable 1
The PWM Timer Counter and PWM Prescale Counter are
enabled for counting.
0
0
The counters are disabled.
1
Counter Reset
1
The PWM Timer Counter and the PWM Prescale Counter
are synchronously reset on the next positive edge of PCLK.
The counters remain reset until this bit is returned to zero.
0
0
Clear reset.
2
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA
3
PWM Enable
1
PWM mode is enabled (counter resets to 1). PWM mode
causes the shadow registers to operate in connection with
the Match registers. A program write to a Match register will
not have an effect on the Match result until the
corresponding bit in PWMLER has been set, followed by the
occurrence of a PWM Match 0 event. Note that the PWM
Match register that determines the PWM rate (PWM Match
Register 0 - MR0) must be set up prior to the PWM being
enabled. Otherwise a Match event will not occur to cause
shadow register contents to become effective.
0
0
Timer mode is enabled (counter resets to 0).
7:4
-
Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
NA