SI2493-C-FT Silicon Laboratories Inc, SI2493-C-FT Datasheet - Page 92

• Manufacturer Part Number: SI2493-C-FT
• Description: 56 KBPS, V.92 ISOMODEM SYSTEM-SIDE - LEAD-FREE TSSOP 0 TO 7
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2493-C-FT

• Mfg Application Notes: SI2493/57/34/15/04, Appl Note AN93
• Data Format: V.21, V.22, V.23, V.29, V.32, V.34, V.90, V.92, Bell 103, Bell 212A
• Baud Rates: 56k
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN93
U71 IO1
Reset settings = 0x0000
3.3.40. U76 (GEN1)
U76 provides control for parallel phone detect (PPD)
intrusion parameters including the off-hook sample rate
(OHSR), absolute current level with modem off-hook
(ACL), ACL update from LVCS (FACL), and the
difference in current between ACL and LVCS that
triggers an off-hook intrusion detection (DCL). All bits in
U76 are read/write (see Table 61).
OHSR[15:9] sets the off-hook loop current sample rate
for intrusion algorithms in 40 ms units. The default value
is 25 (1 sec). The minimum recommended value is 5
(200 ms). The sample rate can be adjusted to much
lower values; however, the likelihood of false intrusion
detections increases sharply with sample rates less
than 520 ms.
Bit 8 (FACL). If FACL = 0
automatically updated to the LVCS value at the sample
rate determined by OHSR. This feature is used to
92
Name
Type
Bit
Bit
3
2
1
0
15:5
Bit
3:1
4
0
D15
Name
OCD
DCD
PPD
RI
Reserved Read returns zero.
Reserved
D14 D13 D12
COMP
Name
PRT
Function
Overcurrent Detect (sticky).
1 = Overcurrent condition has occurred. Clears on :I read.
Parallel Phone Detect (sticky).
1 = Parallel phone detected since last off-hook event. Clears on :I read.
Ring Indicator (sticky).
1 = Ring event has occurred (Si2493/57/34/15/04 on-hook). Clears on :I read.
Data Carrier Detect (status).
1 = carrier detected (inverse of DCD pin).
b
0 – Disables compression (PCM mode).
1 – Enables linear compression.
0 – Disables PCM mode.
1 – Enables PCM mode.
(default), the ACL register is
D11 D10
Table 60. U70 Bit Map (Continued)
D9
Rev. 0.9
D8
ensure the ACL value is continuously updated.
Updating ACL allows host software to determine the
loop current (value returned in ACL) provided the
modem is off-hook longer than the time defined by
U77(IST). Loop current on a particular line can vary
over time due to a variety of factors including
temperature and weather conditions. Updating ACL
reduces the probability of false intrusion detection by
ensuring the ACL reference reflects the most recent off-
hook conditions. If FACL = 1
into ACL by the host. This value is not updated and
remains in the ACL register until overwritten by the host
or until FACL is returned to 0 and updates from LVCS
overwrite the stored value. Writing an initial value to
ACL eliminates the possibility of the modem going off-
hook for the first time simultaneously with an intrusion
and storing the intrusion loop current in ACL.
Bits 7:5 (DCL) set the differential level between ACL
and LVCS that triggers an off-hook PPD interrupt. DCL
D7
Function
D6
D5
COMP
R/W
D4
b
D3
, a value can be written
D2
D1
PRT
R/W
D0