HT818D0 datasheet(9/14 Pages) HOLTEK

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HT818D0

March 15, 2000

· 6Hz/6HzB flash

When voices are playing, the FLAG1 pin

outputs a 6Hz signal to drive an LED. The

signal is active low, 25% duty. Once the voice

output is terminated, the FLAG1 pin be-

comes a floating output. When the FLAG1

and the FLAG2 pins are optioned as 6HzB

and 6Hz outputs, they will be alternately

output at a 6Hz rate.

· Busy output

When a voice group is playing, the outputs of

both FLAG1 and FLAG2 are turned low, indi-

cating that the chip is busy.

In addition to the above-stated output sig-

nals, FLAG1 can also generate one of the fol-

lowing signals by code option:

Voice indicator output

FLAG1 is active low when voices are play-

ing. FLAG1 is also turned low when a voice

section is output. The brightness of FLAG1

varies with the volume. FLAG1 becomes a

floating output after the silence section is

output or the voice output is terminated.

End-pulse output

When the voice output is completed, the

FLAG1 pin outputs an active low pulse. The

pulse width can be programmed depending

on the customer¢s requirements.

The FLAG1 as well as FLAG2 pins are both

floating outputs when the chip is in the

standby state.

Volume control

The function of volume control can be set by

mask option. A code is written in the function

table for the purpose of controlling the volume

of each section output after the volume control

function is chosen. There are two volume op-

tions, namely, full range and half range.

AUD

The AUD pin is a PMOS open drain structure.

It outputs voice signals to drive a speaker

through an external NPN transistor when the

chip is active. The AUD pin becomes a floating

output when the chip is in the standby state.

The 8050 type transistor with hFE@150 is rec-

ommended for an output driver.

AU D

FL A G

: F l oat i n g

AU D

FL A G

: F l oat i n g

VD D

OS C 2

OS C 1

VSS

AU D

R OS C

H T 818D 0

805 0

V DD

SP K

AU D

FL A G

: F l oat i n g

AU D

FL A G

: F l oat i n g

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