HT48E06 datasheet(13/43 Pages) HOLTEK

13 / 43 page

HT48E06

Rev. 0.00

January 12, 2004

Preliminary

The registers status is summarized in the following table.

Reset

(Power On)

WDT Time-out

(Normal Operation)

RES Reset

(Normal Operation)

RES Reset

(HALT)

WDT Time-out

(HALT)*

TMR

xxxx xxxx

uuuu uuuu

TMRC

00-0 1000

uu-u uuuu

Program

Counter

000H

-xxx xxxx

-uuu uuuu

ACC

xxxx xxxx

uuuu uuuu

TBLP

xxxx xxxx

uuuu uuuu

TBLH

--xx xxxx

--uu uuuu

STATUS

--00 xxxx

--1u uuuu

--uu uuuu

--01 uuuu

--11 uuuu

INTC

--00 -000

--uu -uuu

WDTS

0000 0111

uuuu uuuu

1111 1111

uuuu uuuu

PAC

1111 1111

uuuu uuuu

---- -111

---- -uuu

PBC

---- -111

---- -uuu

---- --11

---- --uu

PCC

---- --11

---- --uu

EECR

1000 ----

uuuu ----

Note:

²*² stands for ²warm reset²

²u² stands for ²unchanged²

²x² stands for ²unknown²

Timer/Event Counter

A timer/event counter (TMR) is implemented in the

microcontroller. The timer/event counter contains an

8-bit programmable count-up counter and the clock may

come from an external source or from the system clock.

Using an external clock input allows the user to count

external events, measure time internals or pulse widths,

or generate an accurate time base. Using the internal

clock allows the user to generate an accurate time base.

The timer/event counter can generate PFD signals by

using external or internal clock and the PFD frequency

is determine by the equation fINT/[2

´(256-N)].

There are two registers related to the timer/event coun-

ter; TMR ([0DH]), TMRC ([0EH]). Two physical registers

are mapped to TMR location; writing to TMR makes the

starting value be placed in the timer/event counter

preload register and reading TMR retrieves the contents

of the timer/event counter. The TMRC is a timer/event

counter control register, which defines some options.

The TM0, TM1 bits define the operating mode. The

event count mode is used to count external events,

which means that the clock source comes from an exter-

nal (TMR) pin. The timer mode functions as a normal

timer with the clock source coming from the fINT clock.

The pulse width measurement mode can be used to count

the high or low level duration of the external signal (TMR).

The counting is based on the fINT clock.

In the event count or timer mode, once the timer/event

counter starts counting, it will count from the current

contents in the timer/event counter to FFH. Once over-

flow occurs, the counter is reloaded from the timer/event

counter preload register and generates the interrupt re-

quest flag (TF; bit 5 of the INTC) at the same time.

In the pulse width measurement mode with the TON and

TE bits equal to one, once the TMR has received a tran-

sient from low to high (or high to low if the TE bit is

²0²)it

will start counting until the TMR returns to the original

level and resets the TON. The measured result will re-

main in the timer/event counter even if the activated

transient occurs again. In other words, only one cycle

measurement can be done. Until setting the TON, the

cycle measurement will function again as long as it re-

ceives further transient pulse. Note that, in this operat-

ing mode, the timer/event counter starts counting not

according to the logic level but according to the transient

HT48E06 Datasheet(PDF) 13 Page - Holtek Semiconductor Inc

HT48E06 Datasheet(HTML) 13 Page - Holtek Semiconductor Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

Datasheet Download

Link URL