PC87591L datasheet(134/437 Pages) NSC

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Embedded Controller Modules (Continued)

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Revision 1.07

4.7

MULTI-FUNCTION 16-BIT TIMER (MFT16)

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:

●

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.

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

Features

●

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.

Reload/Capture A

Counter 1

Reload/Capture

Timer/Counter

Timer/Counter and Action

Clock

System

Clock

TBn

& Control

PWM/Capture/Counter Mode Select

TAn

External Event

Interrupt A

Interrupt B

Slow

Clock

Figure 44. MFT16 Functional Diagram

32.768 KHz

Source

and

TnCRA

Timer/Counter 1

TnCNT1

Reload/Capture B

TnCRB

Timer/Counter 2

TnCNT2

Clock

Counter 2

Clock

Pre-Scaler

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