HT815D0 Datasheet, PDF (8/15 Pages) Holtek Semiconductor Inc – 11.2-Second LOG-PCM Speech

HT815D0
That KEY1 functions as a random key is a special
case of sequential key, which combines a particu-
lar arrangement of sub-group playing sequence.
¨ _{Reset of KEY1 playing sequence}
If a sub-group of KEY1 group is being played
and one of KEY2~KEY12 is triggered, the
playing sub-group will be terminated, and
the newly triggered key group is played in-
stead. The first sub-group will start playing
by retriggering KEY1. In other words, the
KEY1 playing sequence is reset whenever a
key other than KEY1 is triggered (see Figure
1).
¨ _{Sub-group selection}
When KEY1 is triggered with pulses, the de-
sired sub-group can be selected by controlling
its corresponding pulse number. However,
the features of KEY1 have to be set in the fol-
lowing ways:
– _{sequential or random}
– _{retriggerable}
– _{minimum key debounce time}
(@700ms, f_OSC=96kHz)
For instance, if sub-group 1-3 is the previous
playing group, sub-group 1-5 will start playing
after 2 pulses are applied to KEY1, and so on.
To make easy selection of KEY1 sub-groups,
one of KEY2~KEY12 should be programmed
as silence. Then this silence key has to be
triggered to reset KEY1. By so doing, the
playing sub-group of KEY1 is directly speci-
fied by the pulse number applied to KEY1
(see Figure 2).
· _{KEY12 as a stop key (by mask option)}
When KEY12 functions as a stop key, any
voice output can be stopped by pressing
KEY12.
· _{KEY1~KEY11 as a repeat key}
KEY1~KEY11 all function as repeat keys if
one of the eleven keys is set as a repeat key. In
other words, once the mode of one of
KEY1~KEY11 is determined, the remaining
10 keys are set accordingly.
As a repeat key, the sections included can be
played sequentially and repeatedly till other
key input is triggered. KEY12 has no other
choice but functions as a stop key when
KEY1~KEY11 are set as repeat keys.
Key features
· _{Key priority}
When two or more keys are triggered simulta-
neously, the output voice is determined by the
key priority as shown below:
KEY1>KEY2>......KEY11>KEY12
· _{Key debounce time}
There are four kinds of key-in debounce time
that can be selected by mask option, namely,
700ms, 22ms, 45ms and 180ms. The key
debounce time varies with the value of the sys-
tem frequency.
· _{Pull-high resistance}
Four kinds of key input pin pull-high resis-
tance can be selected by mask option,
namely, 20kW, 50kW, 100kW and 200kW.
The resistance may vary with VDD, tem-
peratures and the chip itself due to process
variations.
· _{Trigger mode}
All of the 12 keys can be optioned as one-shot
trigger mode, level-trigger mode or level hold
mode.
¨ _{One shot}
When one of the 12 keys (KEY1~KEY12) is
pressed momentarily or held down, the
group corresponding to that key will play
once.
KEY N
AUD
G ro u p N
G ro u p N
8
March 15, 2000