HT48R30A datasheet(17/43 Pages) HOLTEK

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HT48R30A-1

Rev. 1.10

July 2, 2001

Timer/Event Counter

Timer/event counters (TMR) is implemented in

the microcontroller. The timer/event counter

contains an 8-bit programmable count-up coun-

ter and the clock may come from an external

source or from the system clock or RTC.

Using the internal clock sources, there are 2

reference time-bases for timer/event counter.

The internal clock source can be selected as

coming from fSYS (can always be optioned) or

fRTC (enabled only system oscillator in the Int.

RC+RTC mode) by ROM code option. The exter-

nal clock input allows the user to count external

events, measure time intervals or pulse widths,

or to generate an accurate time base and PFD

signals.

Label (TMRC)

Bits

Function

PSC0~PSC2

0~2

To define the prescaler stages, PSC2, PSC1, PSC0=

000: fINT=fSYS/2 or fRTC/2

001: fINT=fSYS/4 or fRTC/4

010: fINT=fSYS/8 or fRTC/8

011: fINT=fSYS/16 or fRTC/16

100: fINT=fSYS/32 or fRTC/32

101: fINT=fSYS/64 or fRTC/64

110: fINT=fSYS/128 or fRTC/128

111: fINT=fSYS/256 or fRTC/256

To define the TMR0 active edge of timer/event counter 0

(0=active on low to high; 1=active on high to low)

TON

To enable/disable timer 0 counting

(0=disabled; 1=enabled)

Unused bit, read as"0"

TM0

TM1

To define the operating mode

01=Event count mode (external clock)

10=Timer mode (internal clock)

11=Pulse width measurement mode

00=Unused

TMRC register

TM 1

TM 0

TM R

TM 1

TM 0

TO N

P u l s e W i dt h

M eas ur e m ent

M ode C o nt r ol

T i m e r / E v ent C ount e r

P r el oad R e gi s t er

Ti m e r / E v e nt

C ount e r

Da t a B u s

R e l oad

O v er f l ow

to I nte r r u p t

1/ 2

8- s t age P r e s c a l e r

8- 1 M U X

f SY S

f IN T

PS C 2 ~ P SC 0

f RT C

R O M C ode O p t i o n

( 1 /2 ~ 1 /2 5 6 )

Timer/Event Counter

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