HT81003 datasheet(5/11 Pages) HOLTEK

5 / 11 page

HT81003/HT81R03

July 24, 2000

Preliminary

System oscillator

The EasyVoiceTM has a built-in RC oscillator

which requires only one external resistor for nor-

mal applications. The oscillator frequency is typi-

cally 2MHz for an external resistor of 150kW. The

required oscillator frequency may vary with differ-

ent sampling rates in the process of voice pro-

gramming. As a result, the value of the oscillator

resistor may be different with respect to different

items.

The oscillator is turned on when triggered by a

key input. After playing, it is immediately turned

off. Then the chip goes into the standby state.

Voice ROM

The voice ROM is originally designed to continu-

ously record the 3-sec voice data at about 5kHz

sampling rate. A higher sampling rate will gener-

ate voices of better playback quality, but will

shorten the total recording time. On the other

hand, a lower sampling rate will result in longer

recording time but sacrifice the voice quality.

The playback time can be significantly extended

by making use of coding efficiency, silence play-

ing, section repeating, section cascade, etc.

Section

Section is the basic element constituting the

contents of the voice ROM. During program-

ming, the customer¢s voice sources can be di-

vided into as many sections as required. A

section can be composed of a voice or an interval

of silence. However, the silent length is not

counted in the voice ROM. The total number of

sections included should be less than 256 due to

the space limitation of the function table ROM.

The total length of the included sections is lim-

ited by the voice ROM.

A section, when triggered by a key input, can be

played once, repeatedly or cascaded with other

sections, depending on the key function table

instructions.

The following are examples of section division:

In addition, a section can be set as retriggerable

or non-retriggerable depending on code option.

· Retriggerable

When the currently playing section is set as

retriggerable, it will stop immediately upon

receipt of other key inputs.

· Non-retriggerable

When the currently playing section is selected

as non-retriggerable, it will go on playing until

the whole section is completed, whether or not

there is a key input in the process of playing.

For a key group, some sections can be set as

retriggerable and some as non-retriggerable.

When a retriggerable section of a key group is

playing, any key can be triggered to interrupt

its playing. If it is a non-retriggerable section

playing, any key interrupt is invalid.

Group

The EasyVoiceTM plays groups according to the

key input. A group can be made up of one or

more sections. When a key is triggered, the cor-

responding group is played. For example, trig-

gering KEY2 plays group 2, and so on. The

same section is allowed to appear in different

groups. However, KEY1 can be made up of mul-

tiple groups when it is optioned as a sequential

key. Otherwise, each key is composed by one

group only.

Key function table

The voice ROM sections are played according to

the instructions of the key function table. The

function table contains group information and

H T 81003/

HT 8 1 R0 3

OS C I

R OS C

se c. 2

s e c . N

se c. 1

s e c . 2

se c. 3

se c. 1

RO M

E x am p l e 1: O ne s e c t i o n o nl y

E x am p l e 2: 3 s ec t i on d i v i s i o n

E x am p l e 3: N s ec t i o n d i v i s i o n

RO M

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