SI3210DCQ1-EVB Silicon Laboratories Inc, SI3210DCQ1-EVB Datasheet - Page 34

• Manufacturer Part Number: SI3210DCQ1-EVB
• Description: DAUGHTERCARD W/SI3201 INTERFACE
• Manufacturer: Silicon Laboratories Inc
• Series: ProSLIC®r
• Type: SLIC/CODECr

Specifications of SI3210DCQ1-EVB

• Contents: Evaluation Board and CD-ROM
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: Si3210
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Si3210/Si3211
2.3.2. Oscillator Frequency and Amplitude
Each of the two tone generators contains a two-pole
resonate
frequency and amplitude, which are programmed via
indirect registers OSC1, OSC1X, OSC1Y, OSC2,
OSC2X, and OSC2Y. The sample rate for the two
oscillators is 8000 Hz. The equations are as follows:
where f
where desired Vrms is the amplitude to be generated;
n = 1 or 2 for oscillator 1 or oscillator 2, respectively.
For example, in order to generate a DTMF digit of 8, the
two required tones are 852 Hz and 1336 Hz. Assuming
the generation of half-scale values (ignoring twist) is
desired, the following values are calculated:
34
OSC1X
OSCnX
n
OSC1
is the frequency to be generated;
=
=
oscillator
Counter
coeff
1
-- -
4
Modulo
1
-- -
4
16-Bit
*Tone Generator 1 Only
n = "1" or "2" for Tone Generator 1 and 2, respectively
OATn
8 kHz
Clock
OITn
coeff
×
×
=
OSCn = coeff
0.21556
-------------------- -
1.78434
1
----------------------- -
1
1 coeff
0.78434 2
n
–
+
=
OATnE
= cos(2 π f
OITnE
coeff
cos
OSCnY = 0,
OSC1Y = 0
circuit


×
(
2π852
---------------- -
Expire
Expire
×
8000
OAT
(
OIT
15
OnE
2
(
15
2
)
15
n
n
–
with
=
/8000 Hz),


x (2
–
1
Figure 20. Simplified Tone Generator Diagram
25701
)
Cross
1
=
Logic
Zero
×
)
Logic
Logic
15
0.78434
×
INT
INT
0.5
a
);
Desired V
------------------------------------ -
=
OZn
1.11 V
=
6465h
programmable
1424
Zero Cross
OSSn
Logic
Load
OnAE
OnAP
OnIE
OnIP
rms
=
rms
590h
REL*
Rev. 1.42
Register
Enable
Load
Resonance
The computed values above would be written to the
corresponding registers to initialize the oscillators. Once
the oscillators are initialized, the oscillator control
registers can be accessed to enable the oscillators and
direct their outputs.
2.3.3. Tone Generator Cadence Programming
Each of the two tone generators contains two timers,
one for setting the active period and one for setting the
inactive period. The oscillator signal is generated during
the active period and suspended during the inactive
period. Both the active and inactive periods can be
programmed from 0 to 8 seconds in 125 µ s steps. The
active period time interval is set using OAT1 (direct
registers 36 and 37) for tone generator 1 and OAT2
(direct registers 40 and 41) for tone generator 2.
To enable automatic cadence for tone generator 1,
define the OAT1 and OIT1 registers and then set the
O1TAE bit (direct Register 32, bit 4) and O1TIE bit
(direct Register 32, bit 3). This enables each of the
timers to control the state of the Oscillator Enable bit,
O1E (direct Register 32, bit 2). The 16-bit counter will
begin counting until the active timer expires, at which
time the 16-bit counter will reset to zero and begin
Two-Pole
Oscillator
8 kHz
Clock
OSC2X
OSCnX
OSCnY
OSCn
OSC2 = 0.49819 (2
=
coeff
1
-- -
4
×
2
0.50181
-------------------- -
1.49819
=
cos
OSC2Y = 0
Routing


Signal
×
2π1336
------------------- -
8000
(
15
2
15
) = 16324 = 3FC4h
–
OnSO


1
)
=
×
0.49819
0.5
to TX Path
to RX Path
=
2370
=
942h