SI2493-D-FS Silicon Laboratories Inc, SI2493-D-FS Datasheet - Page 98

• Manufacturer Part Number: SI2493-D-FS
• Description: IC ISOMODEM SYSTEM-SIDE 16SOIC
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2493-D-FS

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

AN93
5.7.3. U17–U30 (Busy Tone Detect Filter Registers)
U17–U2A set the biquad filter coefficients for stages 1–4 of the busy-tone detection filter, and U2B, U2C, and U2D
set the busy-tone detection output scalar on threshold and off threshold, respectively (see Table 49). The
thresholds are empirically found scalars and have no units. These coefficients are programmed as 16-bit, two’s
complement values. All A0 values are in 3.12 format where 1.0 = 0x1000. All other coefficients are in 1.14 format
where 1.0 = 0xC000. Default values meet FCC requirements.
U2E, U2F, and U30 set the busy cadence minimum total time (BMTT), busy cadence delta time (BDLT), and busy
cadence minimum on time (BMOT), respectively. Settings for busy cadences are specified as a range for ON time
(minimum ON and maximum ON) and a range for OFF time (minimum OFF and maximum OFF). The three values
represented by BMTT, BDLT, and BMOT fully specify these ranges. BMTT (minimum total time) is equal to the
minimum ON time plus the minimum OFF time. BDLT (allowable delta) is equal to the maximum total time
(maximum ON time plus the maximum OFF time) minus the minimum total time (BMTT). BMOT is the minimum
ON time. The values stored in the registers are the hexadecimal representation of the times in seconds multiplied
by 7200. Default values meet FCC requirements (see Figure 26, “Cadence Timing,” on page 100).
98
Register
U1A
U1B
U1C
U1D
U1E
U1F
U2A
U2B
U2C
U2D
U2E
U2F
U17
U18
U19
U20
U21
U22
U23
U24
U25
U26
U27
U28
U29
U30
BT1A0
BT1B1
BT1B2
BT1A2
BT1A1
BT2A0
BT2B1
BT2B2
BT2A2
BT2A1
BT3A0
BT3B1
BT3B2
BT3A2
BT3A1
BT4A0
BT4B1
BT4B2
BT4A2
BT4A1
BMOT
Name
BTON
BTOF
BMTT
BDLT
BTK
Busy-tone detection filter stage 1 biquad coefficients.
Busy-tone detection filter stage 2 biquad coefficients.
Busy-tone detection filter stage 3 biquad coefficients.
Busy-tone detection filter stage 4 biquad coefficients.
Busy-tone detection filter output scaler.
Busy-tone detection ON threshold.
Busy-tone detection OFF threshold.
Busy cadence minimum total time in seconds multiplied by 7200.
Busy cadence delta time in seconds multiplied by 7200.
Busy cadence minimum on time in seconds multiplied by 7200.
Table 49. U17–U30 (Busy Tone Detect Registers)
Rev. 1.3
Description
0xC4F4
0xB50A
Default
0x00A0
0x6EF1
0xC000
0x00A0
0x78B0
0xC305
0x70D2
0xC830
0x80E2
0x00A0
0x0800
0x0000
0x0000
0x0000
0x0000
0x0000
0x4000
0x0400
0x4000
0x0009
0x0070
0x0870
0x25F8
0x0438