NSAM266SA Datasheet, PDF (45/52 Pages) National Semiconductor (TI) – NSAM266SA CompactSPEECHTM Digital Speech Processor with Serial Flash Interface

2 0 Software (Continued)
TABLE 2-2 Tunable Parameters (Continued)
Index Parameter Name
Description
27 DTMF TWIST LEVEL A one-byte value that controls the twist level of a DTMF tone generated by the GT
command by controlling the energy level of each of the two tones (low frequency and
high frequency) composing the DTMF tone The Least Significant Nibble (LSN)
controls the low tone and the Most Significant Nibble (MSN) controls the high tone
The energy level of each tone as measured at the output of a TP3054 codec (before
the DAA) connected to the CompactSPEECH is summarized in the following table
Nibble Value
0
1
2
3
4
5
6
7
8 – 15
Tone energy (dB-Volts)
0
b17 8
b14 3
b12 9
b12 4
b12 0
b11 9
b11 85
b11 85
The volume of the generated DTMF tone during meaurements was 6
(TONE GENERATION LEVELaVOL LEVEL e 6)
For the default level the high tone is b14 3 dBV and the low tone is b12 4 dBV
which gives a DTMF twist level of 1 9 dB
The energy level of a single generated tone is the level of the low tone
28 Reserved
29 Reserved
Default
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Example
TUNE 23 700
Microcontroller 15 17 02 BC
Byte sequence
CompactSPEECH 15 17 02 BC
Description
Set the minimum period for busy
detection to seven seconds
VC
Volume Control vol level
Controls the energy level of all the output generators (play-
back tone generation and voice synthesis) with one com-
mand The resolution is g3 dB
The actual output level is composed of the tunable level
variable plus the vol level The valid range for the actual
output level of each output generator is defined in Table 2-2
For example if the tunable variable VCD LEVEL is 6 and
vol level is b2 then the output level equals VCD LEVEL
a vol level e 4
Example
VC 04
Microcontroller 28 04
Byte sequence
CompactSPEECH 28 04
Description
Set the volume level to VCD LEVEL a
4
WRAM
Write Memory tag data
This command creates a new message with a message tag
tag The following 32 bytes of data data are stored as the
new message data in the message memory
The WRAM command switches the CompactSPEECH to
the MEMORY WRITE state As long as it remains in this
state each subsequent WMEM command appends new
message data to the end of the previous data The
CompactSPEECH remains in the MEMORY WRITE state
until an S command is issued Note that while the Compact-
SPEECH is in the MEMORY WRITE state tag is ignored
If the memory becomes full recording stops and
EV MEMFULL is set in the status word
Example
WMEM 1 32 bytes
Byte sequence
Microcontroller
32 bytes of
17 01
data to write
echo 32 bytes
CompactSPEECH 17 01
of data
Description
Create a message with tag e 01 and
write 32 bytes in the message memory
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