HPC16004 datasheet(20/36 Pages) NSC

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Timer Overview

The HPC46064 contains a powerful set of flexible timers

enabling the HPC46064 to perform extensive timer func-

tions not usually associated with microcontrollers

The

HPC46064 contains nine 16-bit timers Timer T0 is a free-

running timer counting up at a fixed CKI16 (Clock Input

16) rate It is used for WATCHDOG logic high speed event

capture and to exit from the IDLE mode Consequently it

cannot be stopped or written to under software control Tim-

er T0 permits precise measurements by means of the cap-

ture registers I2CR I3CR and I4CR A control bit in the

ture registers I2CR I3CR and I4CR respectively record the

value of timer T0 when specific events occur on the inter-

rupt pins I2 I3 and I4 The control register IRCD programs

the capture registers to trigger on either a rising edge or a

falling edge of its respective input The specified edge can

also be programmed to generate an interrupt (see

Figure

19 )

TLDD11372 17

FIGURE 19 Timers T0 T1 and T8 with

Four Input Capture Registers

The HPC46064 provides an additional 16-bit free running

timer T8 with associated input capture register EICR (Ex-

ternal Interrupt Capture Register) and Configuration Regis-

ter EICON EICON is used to select the mode and edge of

the EI pin EICR is a 16-bit capture register which records

the value of T8 (which is identical to T0) when a specific

event occurs on the EI pin

The timers T2 and T3 have selectable clock rates The

clock input to these two timers may be selected from the

following two sources an external pin or derived internally

by dividing the clock input Timer T2 has additional capabili-

ty of being clocked by the timer T3 underflow This allows

the user to cascade timers T3 and T2 into a 32-bit timer

counter The control register DIVBY programs the clock in-

put to timers T2 and T3 (see

Figure 20 )

The timers T1 through T7 in conjunction with their registers

form Timer-Register pairs The registers hold the pulse du-

ration values All the Timer-Register pairs can be read from

or written to Each timer can be started or stopped under

software control Once enabled the timers count down and

upon underflow the contents of its associated register are

automatically loaded into the timer

SYNCHRONOUS OUTPUTS

The flexible timer structure of the HPC46064 simplifies

pulse generation and measurement There are four syn-

chronous timer outputs (TS0 through TS3) that work in con-

junction with the timer T2 The synchronous timer outputs

can be used either as regular outputs or individually pro-

grammed to toggle on timer T2 underflows (see

Figure 20 )

TLDD11372 18

FIGURE 20 Timers T2 – T3 Block

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