SI3230 Datasheet, PDF (30/108 Pages) Silicon Laboratories – PROSLIC® PROGRAMMABLE CMOS SLIC WITH RINGING/BATTERY VOLTAGE GENERATION

Si3230
Table 26. Registers for Ringing Generation (Continued)
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).
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:
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. Figure 13
illustrates a trapezoidal ringing waveform with offset
V_ROFF.
V_TIP-RING
where
RCO = coeff × (2¹⁵)
V_ROFF
T=1/freq
coeff = cos_{⎝⎛1}----₀---₀-²---₀^π----^f-_H-----_z-_⎠⎞
and f = desired ringing frequency in hertz.
t_RISE
time
RNGX
=
-¹-
4
×
-¹----–-----^c---^o----^e----^f--^f
1 + coeff
×
2¹⁵
×
D_-----e_----s_---i_--r_--e_----d_------V_{----P---K----}(_--0_------t_--o_-----9_----4_---._--5_-----V_-----)
96 V
RNGY = 0
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 V_PK 20 Hz ringing signal, the
equations are as follows:
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:
RNGY
=
-¹-
2
× Period × 8000
coeff
=
cos
⎛
⎝
1^--2--0^--π-0^---0^-×----2-H^---0--z^{-⎠⎞}
=
0.99211
RCO = 0.99211 × (2¹⁵) = 32509 = 7EFDh
RNGX
=
-¹-
4
×
0_----._-0_----0_---7_---8_----9_--
1.99211
×
2¹⁵
×
7_----0_--
96
=
376
=
0177h
RNGY = 0
RNGX
=
-^D----^e----^s---ⁱ--^r--^e----^d------^V----^P---^K--
96 V
×
(
2¹⁵
)
RCO
=
---²-----^×-----^R-----^N----^G-----^X-----
t_RISE × 8000
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
30
Preliminary Rev. 0.96