Si3230
30
Preliminary Rev. 0.96
Not
Recommended
fo
r N
ew
D
esi
gn
s
When
the
ringing
state
is
invoked
by
writing
LF[2:0] = 100 (direct Register 64), the ProSLIC will go
into the ringing state and start the first ring. At the
expiration of RAT, the ProSLIC will turn off the ringing
waveform and will go to the on-hook transmission state.
At the expiration of RIT, ringing will again be initiated.
This process will continue as long as the two timers are
enabled and the Linefeed Control register is set to the
ringing state.
2.4.2. Sinusoidal Ringing
To configure the ProSLIC for sinusoidal ringing, the
frequency and amplitude are initialized by writing to the
following indirect registers: RCO, RNGX, and RNGY.
The equations for RCO, RNGX, RNGY are as follows:
where
and f = desired ringing frequency in hertz.
In selecting a ringing amplitude, the peak TIP-to-RING
ringing voltage must be greater than the selected on-
hook line voltage setting (VOC, direct Register 72). For
example, to generate a 70 VPK 20 Hz ringing signal, the
equations are as follows:
In addition, the user must select the sinusoidal ringing
waveform by writing TSWS = 0 (direct Register 34,
bit 0).
2.4.3. Trapezoidal Ringing
In addition to the sinusoidal ringing waveform, the
ProSLIC
supports
trapezoidal
ringing.
illustrates a trapezoidal ringing waveform with offset
VROFF.
Figure 13. Trapezoidal Ringing Waveform
To configure the ProSLIC for trapezoidal ringing, the
user should follow the same basic procedure as in the
Sinusoidal Ringing section, but using the following
equations:
RCO is a value which is added or subtracted from the
waveform to ramp the signal up or down in a linear
fashion. This value is a function of rise time, period, and
Ringing frequency
15 to 100 Hz
RCO[15:0]
Indirect Register 20
Ringing amplitude
0 to 94.5 V
RNGX[15:0]
Indirect Register 21
Ringing initial phase
Sets initial phase for
sinewave and period
for
trapezoid
RNGY[15:0]
Indirect Register 22
Common Mode Bias Adjust During Ringing
0 to 22.5 V
VCMR[3:0]
Indirect Register 40
Note:
The ProSLIC uses registers that are both directly and indirectly mapped. A “direct” register is one that is mapped
directly. An “indirect” register is one that is accessed using the indirect access registers (direct registers 28 through
31).
Table 26. Registers for Ringing Generation (Continued)
RCO
coeff
2
15
=
coeff
2
f
1000 Hz
-----------------------
cos
=
RNGX
1
4
---
1coeff
–
1coeff
+
------------------------
2
15
Desired V
PK 0to94.5 V
96 V
------------------------------------------------------------------------
=
RNGY
0
=
coeff
2
20
1000 Hz
-----------------------
0.99211
=
cos
=
RCO
0.99211
2
15
32509
7EFDh
==
=
RNGX
1
4
---
0.00789
1.99211
---------------------
2
15
70
96
------
376
0177h
=
RNGY
0
=
time
VROFF
T=1/freq
tRISE
VTIP-RING
RNGY
1
2
---
Period
8000
=
RNGX
Desired V
PK
96 V
-----------------------------------
2
15
=
RCO
2
RNGX
t
RISE
8000
---------------------------------
=