p89lpc932ba NXP Semiconductors, p89lpc932ba Datasheet - Page 28

• Manufacturer Part Number: p89lpc932ba
• Description: P89lpc932 8-bit Microcontroller With Accelerated Two-clock 80c51 Core 8 Kb Flash With 512-byte Data Eeprom And 768-byte Ram
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 12379
Product data
8.18.4 Output compare
8.18.5 Input capture
8.18.6 PWM operation
There are four output compare channels A, B, C and D. Each output compare
channel needs to be enabled in order to operate and the user will have to set the
associated I/O pin to the desired output mode to connect the pin. When the contents
of the timer matches that of a capture compare control register, the Timer Output
Compare Interrupt Flag (TOCFx) becomes set. An interrupt will occur if enabled.
Input capture is always enabled. Each time a capture event occurs on one of the two
input capture pins, the contents of the timer is transferred to the corresponding 16-bit
input capture register. The capture event can be programmed to be either rising or
falling edge triggered. A simple noise filter can be enabled on the input capture by
enabling the Input Capture Noise Filter bit. If set, the capture logic needs to see four
consecutive samples of the same value in order to recognize an edge as a capture
event. An event counter can be set to delay a capture by a number of capture events.
PWM operation has two main modes, symmetrical and asymmetrical.
In asymmetrical PWM operation the CCU Timer operates in downcounting mode
regardless of the direction control bit.
In symmetrical mode, the timer counts up/down alternately. The main difference from
basic timer operation is the operation of the compare module, which in PWM mode is
used for PWM waveform generation.
As with basic timer operation, when the PWM (compare) pins are connected to the
compare logic, their logic state remains unchanged. However, since bit FCO is used
to hold the halt value, only a compare event can change the state of the pin.
Fig 8. Asymmetrical PWM, downcounting.
Rev. 04 — 06 January 2004
8-bit microcontroller with accelerated two-clock 80C51 core
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
002aaa534
P89LPC932
TOR2
COMPARE VALUE
TIMER VALUE
0x0000
NON-INVERTED
INVERTED
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