pc87591l National Semiconductor Corporation, pc87591l Datasheet - Page 134

• Manufacturer Part Number: pc87591l
• Description: Lpc Mobile Embedded Controllers
• Manufacturer: National Semiconductor Corporation

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Embedded Controller Modules
4.7
The PC87591x includes two Multi-Function Timer (MFT) modules. The registers of each module are prefixed with Tn and
the signals are suffixed with an n (where n is the module’s number, i.e., 1 or 2). Each MFT16 module consists of two func-
tional units designed to satisfy a wide range of application requirements. The units include:
Figure 44 shows the contents of an MFT16 and the top-level interaction. The rest of the section describes an MFT16 module.
4.7.1
Clock Source Unit that contains a pre-scaler with one clock source selector for each counter.
Main timer/counter and action unit that contains two counters, two reload registers for PWM, Input Capture or
Counter modes.
Mode selector/control unit that defines the function of the I/O pins and the interrupts.
Two 16-bit programmable timers/counters
Two 16-bit reload/capture registers. These registers are used either as reload registers or capture registers, depend-
ing on the mode of operation.
A 5-bit fully programmable clock pre-scaler
Clock source selectors for each counter. These enable each counter to operate in:
— Pulse accumulate mode
— External event mode
— Prescaled system clock mode
— Slow speed clock input mode (where applicable)
Two I/O pins (TAn and TBn), with programmable edge detection; these operate as:
— Capture inputs
— Capture and preset inputs
— External event (clock) inputs
— PWM outputs
Two interrupts, one for each counter, that can be generated/ triggered by:
— Timer underflow
— Timer reload
— Input capture
Four pending bits, which can be polled by software, are associated with the two interrupts.
32.768 KHz
External Event
System
Clock
MULTI-FUNCTION 16-BIT TIMER (MFT16)
Slow
Clock
Features
Reload/Capture
Timer/Counter
Pre-Scaler
Source
Clock
and
Counter 1
Counter 2
Clock
Clock
Figure 44. MFT16 Functional Diagram
PWM/Capture/Counter Mode Select
(Continued)
Timer/Counter and Action
Reload/Capture A
Reload/Capture B
Timer/Counter 1
Timer/Counter 2
TnCNT1
TnCNT2
TnCRA
TnCRB
& Control
134
Interrupt B
Interrupt A
Revision 1.07
TAn
TBn