ADP315PC87570 National Semiconductor, ADP315PC87570 Datasheet - Page 106

• Manufacturer Part Number: ADP315PC87570
• Description: Keyboard and Power Management Controller
• Manufacturer: National Semiconductor

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
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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)
32.768 KHz
External Event
System
Clock
Slow
Clock
Reload/Capture
Timer/Counter
Source
Clock
Unit
Counter 2
Counter 1
Clock
Clock
Figure 14-1. MFT16 Functional Diagram
Multi-Function 16-Bit Timer (MFT16)
PWM/Capture/Counter Mode Select
Timer/Counter and Action
Reload/Capture A
Reload/Capture B
Timer/Counter 1
Timer/Counter 2
TCNT1
TCNT2
TCRA
TCRB
& Control
106
14.2 FUNCTIONAL DESCRIPTION
The MFT16 module consists of two functional units:
Figure 14-1 illustrates the contents of the MFT16 and their
top level interaction.
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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.
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.
Interrupt B
Interrupt A
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TA
TB