PC87570-ICCSLASHVUL datasheet(106/168 Pages) NSC

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Multi-Function 16-Bit Timer (MFT16)

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14.0 Multi-Function 16-Bit Timer (MFT16)

The MFT16 contains two independent 16-bit timer/counters.

It can operate from several clock sources in Pulse Width

Modulation (PWM), Capture or Counter mode in order to

satisfy a wide range of application requirements.

14.1 FEATURES

• Two 16-bit programmable timers/counters

• Two 16-bit reload/capture registers which function ei-

ther as reload registers or as capture registers, depend-

ing on the mode of operation

• A 5-bit fully programmable clock prescaler

• Clock source selectors for each counter which 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 (TA and TB) with programmable edge de-

tection which operate as:

— Capture inputs

— Capture and preset inputs

— External event (clock) inputs

— PWM outputs

• Two interrupts, one for each counter, which can be gen-

erated/ triggered by:

— Timer underﬂow

— Timer reload

— Input capture

Four pending bits, which can be polled by the user soft-

ware, are associated with the two interrupts.

14.2 FUNCTIONAL DESCRIPTION

The MFT16 module consists of two functional units:

• A Clock Source Unit which contains a 5-bit prescaler

and two separate clock source selectors, one for each

counter.

• The main timer/counter and action unit which contains

two counters, two reload registers, and a mode selec-

tor/control unit which defines the function of the I/O pins

and the interrupts.

Figure 14-1 illustrates the contents of the MFT16 and their

top level interaction.

Reload/Capture A

Counter 1

Reload/Capture

Timer/Counter

Timer/Counter and Action

Clock

System

Clock

& Control

PWM/Capture/Counter Mode Select

External Event

Interrupt A

Interrupt B

Slow

Clock

Figure 14-1. MFT16 Functional Diagram

32.768 KHz

Source

Unit

TCRA

Timer/Counter 1

TCNT1

Reload/Capture B

TCRB

Timer/Counter 2

TCNT2

Clock

Counter 2

Clock

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