OK.I Semiconductor MSM5205 ADPCM SPEECH SYNTHESIS LSI

OK.I Semiconductor MSM5205 ADPCM  SPEECH  SYNTHESIS  LSI
OK.I Semiconductor
MSM5205
ADPCM SPEECH SYNTHESIS LSI
TO CUSTOMERS FOR NEW CIRCUIT DESIGN
For a new circuit design, it is recommended to
use the MSM6585 as described later. The
MSM5205 has a 1O-bi t DA converter and does
not have a built-in low-pass filter. On the
other hand, the MSM6585 has a l2-bit DA
converter and includes a -40dB/ oct low-pass
filter. The sampling frequency can also be
selected up to 32kHz. Therefore, the MSM6585
can realize a high quality voice.
GENERAL DESCRIPTION
The MSM5205 is fabricated using Oki's ad­
vanced CMOS process which enables low­
power consumption. The single power sup­
ply requirement and its availability in l8-pin
molded DIP allow the MSM5205 to be ideally
suited for various applications.
The MSM5205 is a speech synthesis integrated
circuit which accepts Adaptive Differential
Pulse Code Modulation (ADPCM) data. The
circuit consists of synthesis stage which ex­
pands the 3- or 4-bit ADPCM data to l2-bit
Pulse Code Modulation (PCM) data and a D/
Astage which reproduces analog signals from
the PCM data.
FEATURES
•
•
•
•
3 or 4-bit ADPCM system
On-chip 10-bit D/ A converter
Low power consumption
( 10 mW typical)
Single +5V supply
Wide operating temperature
(Ta = -30°C - +70°C)
18-pin Plastic DIP
(DIP l8-P-300)
•
•
BLOCK DIAGRAM
4·brt
Input
RESET
AOPCM syntheSis stage
raglster
4Bi38
12
�
f
S,
12·blt
Timing
Circuit
shift
register
8,
10
10·bit
DA
DAOUT
VCK
VSS VDD
-
6724240 0016232 506 -
T,
T2
37
OK.I Semiconductor
MSM5205
PIN CINFIGURATION
S1
18 VDD
1
S2 2
17 Xl'
4Bt3B 3
16 XT
Do
01
15
4
5
RESET
14 VCK
01 6
13 T1
03 7
12 Tl
NC
8
11
NC
VSS 9
10
DAOUT
ABSOLUTE MAXIMUM RATINGS
Parameter
Conditions
Symbol
Ratings
VDD
Ta
=
25°C
--{).3
Input voltage
VIN
Ta
=
25°C
-0.3
Power dissipation
PD
Ta
=
25°C
Power supply voltage
Storage temperature
Note:
-
+7.0
V
VDD
V
200 max
-
Tslg
-
-55
-
Unit
+ 150
mW
°C
Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operational section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
OPERATING CONDITIONS
Parameter
..
Symbol
Conditions
Power supply voltage
VOD
-
Operating tem perature
Top
-
Oscillator Frequency
fosc
Specified Oscillator
6724240 0016233 442 ..
38
r
Ii
I
I
Ratings
+3
-
+6
Unit
V
- 30 - +70
°C
384 -768
kHz
OK.I Semiconductor
MSM5205
D.CJA.C. CHARACTERISTICS
(VDD 5V±5%; Ta -30·C - +70°C, unless otherwise noted)
=
=
Parameter
Conditions
Symbol
VIH
Input High Voltage
Input low Voltage
VIL
Input High Current
hH
Input low Current
IlL
Min.
Typ.
Max.
Unit
All inputs except h T2
4.2
VDD+0.3
V
All inputs except T1. T2
Vss-O.3
-
0.8
V
VDD
-
-
1
IJA
OV
-
-
-1
IJA
-
-
IJA
-
IJA
VIN
=
VIN
=
-
Output High Current
I OH
VCK pin: Vo = 4.2V
- 50
Output low Current
10L
VCK pin: Vo = O.4V
+50
-
Operating Current
IDo
fose 384 kHz
VDD 5V
-
2
4
mA
D/A Accuracy
(Internal 1O-bit D/A)
VE
-
:1:4
-
lSB
DAOUT
Output Impedance
VOR
-
100
=
=
Full Scale; VOD
II
I
=
-
5V
I
I
I
-
k!1
PIN DESCRIPTION
Pin Name
Terminal Number
S1
S2
1
I/O
2
These inputs select the sampling data according to Figure 1.
48/38
3
Specifies whether 3-bit or 4-bit ADPCM data is to be processed. "H" level input is 4-bit (ADPCM). "l" level input is 3bit (AOPCM).
ADPCM data inputs. For 3-bit ADPCM data. Do input is not used and should be connected to ground.
VSS
I
9
Ground (0 V)
10
DAOUT
o
Output for synthesized analog signal. Peak-to-peak swing is proportional to VOO. Typical method of connection is
shown Rgure 2
12
13
IC test pins used at the factory for testing purposes only. During normal operations, T1 is grounded and T2 is left
open.
14
o
This pin outputs a signal whose frequency is equal to the sampling frequency selected by the S1. S2 inputs. See the
ftgure1.
..
6724240 001 6234 389 ..
39
OKI Semiconductor
MSM5205
PIN DESCRIPTION
(continued)
Pin Name
Terminal Number
RESET
15
I/O
An active high input which initializes the internal circuitry. Internally, the reset pulse is synchronized with the VCK
signal. To be effective, it must be true for at least twice VCK time.
XT
16
XT
17
I
o
Oscillator input and output for a crystal or ceramic resonator (Figure
3).
18
VDO
Power supply pin (Typical +5V)
S1
S2
Sampling Frequency (fosc=384kHz)
L
L
4 kHz (fosc 196)
L
H
6 kHz (fosc 164)
to select
H
L
8 kHz (fosc 148)
A 768kHz oscillator can be used
H
H
Prohibited
Note: *1 A 384kHz oscillator can be used
See Note *1
4kHz, 6kHz or 8kHz.
to select 8kHz, 12kHz or 16kHz.
Figure 1
Speaker
AMP
»)
Cut off frequency (fCUT) of LPF should be related to the selected sampling frequency (f sample) by,
(fCUT)
=
f sample/2 x 0.85
Sound quality is strongly dependent on the characteristiC of the low pass filter.
•
If the MSM5205 is sent a stream of AOPCM data that causes greater than full scale output, the
O/A output will wrap around: from the most positive rail (+5V) to the most negative rail (O.OV)
Figure 2
XT(16}IN
1
XT and XT (Oscillator connector pins)
Figure 3
..
6724240 001 6235 215 ..
40
{
X:384kHz
Cr220pF
C2:220pF
}
{
Murata Corporation
CSB 3840 (ceramic resonator)
Or as required to
match crystal or
ceramic resonator
load specifications.
OKI Semiconductor
MSM5205
DA converter SN ratio improvement
method
The accuracy near center of the voice wave­
form of this LSI may be worse due to the
configuration of the DA converter. There­
fore, the S N ratio can be improved by shifting
the waveform center up or down. This is an
extremely effective method for improving
the SN ratio of a small signal or improving
residual noise during silence (between 2
speech patterns.)
To put it concretely, by adding data before
or after the current ADPCM data (voice
data), the wavcform center can be shifted as
shown in Figure 4.
Adding data is as follows:
Since an offset of about 5 mV can be ob­
tained for each 2 samples of data, it is recom­
mended that about 100 samples of data be
entered to shift the waveform center about
250 mY.
For 3-bit data, an offset of about5mV can be
obtained for each data.Therefore, about 50
samples of data is required to be entered to
shift the waveform center about 250 mY.
In the (A) section, the waveform center
should be shifted up. In the (8) section, the
waveform center should be shifted down.
The number of da ta in the (A) section should
be the same as that in the (B) section.
When (A) is added before voice data and (B)
is added after the voice data, the output
waveform is as shown in Figure 4.
(B) section
(A) section
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
Since the dynamic range is narrowed by the
shifted area, some data may overflow,
causing the voice to be distorted.
100 data
(The ADPCM bit length is 4-bit.)
If this occurs, decrease the sound level about
20% and analyze the data once again. (For
an overflow, see the precautions for ADPCM
data creation on the next page.)
1
VDD
2
(25Vj
Figure 4 Waveform the DA Converter
Note 2:
..
Voice data should be sufficiently small just prior to (8). For voice editing. insert a silence of about
10msec .
6724240 0016236 151 ..
41
OK.I Semiconductor
MSM5205
Precaution for ADPCM data creation
the data. If this occurs, analyze and create
the ADPCM data once again.
When voice is synthesized by the MSM 5205
using ADPCM data analyzed by the
MSM 5218, noise may be generated in the
synthesized voice.
An example of a waveform when an over­
flow occurs and the overflow protection
method is as follows:
The MSM 5205 is not equipped with an
overflow protection unit in the internal op­
era tion circuit even though theMSM 5218is.
Therefore,aithough theMSM5218produces
normal voice, theMSM5205 may cause noise
in the composi te voice due to an overflow in
(1)
Waveform when an overflow occcurs
The observation of the output waveform
from the DA converter of the MSM S20S on
an oscilloscope shows that an overflowed
waveform is looped as shown in Figure 5.
VDD
__
L
__
____
___
____
_
LVDD
2
OV
Overflow sectIOn
Figure 5 Output Wavefonn When an Overflow Occurs
(2)
Overflow protection method
Even if an input waveform is not beyond the
dynamic range when the ADPCM data is
analyzed by the M SM 5218, the output
waveform may overflow due to an internal
operation error.
Therefore, if the maximum amplitude level
of the input waveform when the ADPCM
data is analyzed by the M SM 5218, is con­
trolled to about 80% of the dynamic range or
less (see Figure 6), the output waveform of
the MSM5205 will not overflow, causing no
noise in the composite voice.
-------
VDO
9
1(jVOD
-'L voo
2
1
VDO
16
------- OV
Figure 6 Waveform When the Maximum Amplitude Level of the Input Waveform
is about 80% of the Dynamic Range.
42
_
6724240 0016237 098 _
OK.I Semiconductor
MSM5205
Figure 7 shows the time chart for MSM520S.
TIME CHART
VCK(O)
RESET (I)
At least twice To
I
I
I
IIC INTERNAL]
RESET TIMING
00- 03 (I)
INPUT TIMING
:I
I
I
Note 3:
I
I
I
I
�.�����M�l,,�������--�
I
I
__________________
I
I
[IC INTERNAL)
00- 03
OATA CAPTURE TIMING
OAOUT (0)
SS
II
iI
-I r-
15.6�sec
I
I
I!
I
I
I
%
I
I
I
I
I
I
I
:��
�
-1.5.2�sec
------------------------
See the RESET pin description about RESET timing of the IG internal.
Figure 7
..
6724240 0016238
T24 ..
43
OKI Semiconductor
MSM5205
THE FOLLOWING TIMING SHOWS HOW TO APPLY THE RESET
VCK(O)
RESET (I)
: I�������--�--�------�
!fJ
I
At least twice To
[IC internall _________ ______-i
L--'--.!..--'�_'_
___'_____'q"'"}
RESET timing
--'
____
________
__
Figure 8 MSM5205 Reset Timing
VCK(O)
Reset latch timmg
RESET (I)
[IC Internall
RESE T liming
f.---- 125 �sec ---l
J
I
rl----�
,
'
'-'
, , Note4
l!-. -!---,
�
____
: 7 8IJsec (3 x 1/384 kHz)
'-------'I
:I
+-_ _ ___ _-+_ _ _ _ __ _ __
______
"
---:lL_N�ol::.
e 4�
...
'_________________'_______________ __ ___
__________
Figure 9 MSM5218 Reset Timing (8 kHz Sampling Example)
Note 4:
The reset signal is latched within the LSI by the reset latch timing. Analysis is commenced by switching
the external reset signal from H to L before this timing. Switching is probably best achieved by the
leading edge of the VGK signal.
DISTINCTION BETWEEN MSM5218 AND MSM5205
Both S ynthesis stages (MSM 5218 and
MSM52 05) work with the same method,
however , with the exception that MSM 5218
is equipped with an overflow protection.
In other words, when all 12-bit PCM become
'I' any further exceeding analog input would
cause a data overflow which is caught and
re-routed as the MSB in case of MSM 5218.
MSM5205 returns to 'all bits zero' when a
data overflow occurs .
..
6724240 001 6239 9 60 ..
44
Therefore, the DA output of MSM5205 is
distorted badly.
When MSM 52 18 is being used to generate
ADPCM data for playback on MSM 52 05,
the peak to peak input level to the AD
converter should be limited to 8 0% of the
converters maximum input range.
The use of an automatic gain control (AGe)
amplifier or a hard limiter is recommended.
OKI Semiconductor
MSM5205
TYPICAL APPLICATION
MSM5205 TO CENTRONICS INTERFFACE CIRCUITS (fSAM
Figure 10 shows the MSM5205 to centronics
interface circuit (fSAM = 8kHz), and Figure 11
=
8kHz)
shows that timing chart.
BUSY
STROBE
RESET
100K
-RES
Do
01
DATA
02
13
7
Os
12
6 Do
6
D.
4019
D,
10
0.
07
�
15
5
03
1
;
2
VOO
I I
1
AUOIO
SPEAKER
DAOUT
4 Do
Vss
1+ 10+5
01�F
-
MSM5205RS
D1
8
10�F
•
11
/T
220pF =
Figure 10
MSM5205 to Centronics Timing Diagram
RESET (I )
RES
�'----
_____________________
-----e:==
STROBE
DATA
MIN 250 �sec
==:J'------
-:-:-:
__
X first byte
X
�
:-_____
-
VCK (0)
high mbble
KB���
�I
__________________
BUSY
___
\
...J
______
--.Jf
_____ _____
Figure 11
..
2 ..
6724240 0016240 68
45
OKI Semiconductor
MSM5205
•
MSM5205 VOICE SYNTHESIS CIRCUIT
linked together is shown in Figure 12. The
timing chart for this example is provided in
Figure 13.
EXAMPLE
An example where 256k-bit EPROM are used
+------++--; LPF
(MSM4025)
Figure 12
..
6724240 0016241 519 ..
46
� »))
OKI Semiconductor
M5205 VCK (0)
START SW
M4013 S,
MSM5205
nrlJl..Jl----- ------------------------------------ ---JUU
JlL-______________________
l
~
I
_u _______ ~
_u
M4013 Qj
(M5205 RESET)
M4013 O2
(4 low order bits)
Q2
(4 high order bits)
M4040 0 ,
________
~-------------------------~
~-------------------------~
~---------------------~
~--------------~
_ _ _ _----lr--nL_J--trl_fL
M404D 03
______
---Irm-u-~
------------------------~~
Figure 13
. . b724240 001b242 455 . .
47
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