si3210 ETC-unknow, si3210 Datasheet - Page 38

• Manufacturer Part Number: si3210
• Description: Proslic Programmable Cmos Slic/codec With Ringing/battery Voltage Generation
• Manufacturer: ETC-unknow

Si 3210/ Si3 211/S i32 12
The pulse metering oscillator has a volume envelope
(linear ramp) on the on/off transitions of the oscillator.
The volume value is incremented by the value in the
PLSD register (indirect Register 23) at an 8 kHz rate.
The sinusoidal generator output is multiplied by this
volume before being sent to the DAC. The volume will
ramp from 0 to 7FFF in increments of PLSD so the
value of PLSD will set the slope of the ramp. When the
pulse metering signal is turned off, the volume will ramp
to 0 by decrementing according to the value of PLSD.
38
Pulse Metering Inactive Timer
Note: The ProSLIC uses registers that are both directly and indirectly mapped. A “direct” register is one that is mapped
Pulse Metering Attack/Decay
Pulse Metering Active Timer
Figure 22. Pulse Metering Volume Envelope
Pulse Metering Frequency
Pulse Metering Amplitude
Pulse Metering Control
Pulse Metering Oscillator
8 Khz
directly. An “indirect” register is one that is accessed using the indirect access registers (direct registers 28
through 31).
Ramp Rate
Parameter
Coefficient
Coefficient
Volum e
Clip to 7FFF or 0
Table 31. Associated Pulse Metering Generator Registers
+/–
X
Status and control registers
0 to PLSX (full amplitude)
Sets oscillator frequency
Sets oscillator amplitude
Description / Range
0 to 8 sec
0 to 8 sec
To DAC
PLSD
Preliminary Rev. 1.11
DTMF Detection
The dual-tone multi-frequency (DTMF) tone signaling
standard is also known as touch tone. It is an in-band
signaling system used to replace the pulse-dial
signaling standard. In DTMF, two tones are used to
generate a DTMF digit. One tone is chosen from four
possible row tones, and one tone is chosen from four
possible column tones. The sum of these tones
constitutes one of 16 possible DTMF digits.
DTMF Detection Architecture
DTMF detection is performed using a modified Goertzel
algorithm to compute the dual frequency tone (DFT) for
each of the eight DTMF frequencies as well as their
second harmonics. At the end of the DFT computation,
the squared magnitudes of the DFT results for the eight
DTMF fundamental tones are computed. The row
results are sorted to determine the strongest row
frequency; the column frequencies are sorted as well.
At the completion of this process, a number of checks
are made to determine whether the strongest row and
column tones constitute a DTMF digit.
The detection process is performed twice within the
45 ms minimum tone time. A digit must be detected on
two consecutive tests following a pause to be
recognized as a new digit. If all tests pass, an interrupt
is generated, and the DTMF digit value is loaded into
the DTMF register. If tones are occurring at the
maximum rate of 100 ms per digit, the interrupt must be
serviced within 85 ms so that the current digit is not
PSTAT, PMAE,
Register Bits
PMIE, PMOE
PLSCO[15:0]
PLSD[15:0]
PLSX[15:0]
PAT[15:0]
PIT[15:0]
Direct Registers 44 & 45
Direct Register 46 & 47
Indirect Register 25
Indirect Register 24
Indirect Register 23
Direct Register 35
Location