SI2493-C-FS Silicon Laboratories Inc, SI2493-C-FS Datasheet - Page 180

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

Specifications of SI2493-C-FS

• 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: UART
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN93
Si2493/57/34/15/04/Si3008
Prototype Bring-Up Guide*
*Note: Pin numbers refer to FS package.
This section provides help with the debugging of initial
prototypes. Although most ISOmodem
designs function as expected, there is the potential for
layout errors, omitted or incorrect components used in
the initial assembly run, and host software problems. If
the prototype modem does not function correctly, the
techniques outlined in this guide will help to quickly
isolate the problem and get the prototype functioning
correctly. A functional Si24xxURT-EVB and data sheet
and a computer with HyperTerm is required for some of
the troubleshooting steps. It is assumed that the
designer has read the data sheet, used the reference
design
carefully
troubleshooting steps begin with system-level checks
and proceed to the component level.
Visual Inspection
Before troubleshooting, be certain that the circuit boards
and components are clean. Carefully wash the boards
to remove all solder flux and solder flakes. Inspect the
modem circuitry to ensure all components are installed,
and inspect all solder joints for incomplete connections,
cold solder joints, and solder bridges. Check all
polarized components, such as diodes, Zener diodes,
and capacitors for correct orientation. Thoroughly clean
the circuit board after replacing a component or
soldering any connections.
Reset the Modem
Be sure the modem is properly reset after power is
applied and stable.
Basic Troubleshooting Steps
180
Check Power
With power off, use an Ohm meter to verify that
system ground is connected to Si24xx pin 12. Turn
on system power and measure the voltage between
pins 4 and 12 and between pins 12 and 13 on the
Si2401. In both cases, the voltage should be 3.3 V. If
this is not the case, check the power routing. If
power is present, go to the next step.
Check Phone Line
Check the phone line with a manual telephone to be
sure there is a dial tone and dialing is possible. The
dc voltage across TIP and RING should read
approximately 40–52 V with the phone on-hook.
and
followed
recommended
the
layout
bill-of-materials,
guidelines.
®
prototype
The
and
Rev. 0.9
Check modem configuration
Read back the modem register settings and correct any
inconsistencies. Use the ATSR or ATr# commands to
list the contents of the S-Registers.
If the problem was not located with these basic
troubleshooting steps, it is time to narrow the problem
down to the host system (hardware and software), the
Si24xx chip (and associated components), or the
Si3008 (and associated components).
AT OK?
The modem responds with an “O” to the command
“AT<cr>.”
This
communicating with the modem controller and problems
are in one of the following areas:
Reset Modem
Do a manual reset on the modem. Hold Si24xx pin 8
(RESET) low for 300 ms; return to V
less than 5 ms, and wait for at least 300 ms before
executing the first AT command.
Check DTE Setup
Be sure the DTE (Host) serial port is configured the
same as the modem. The default condition is eight
data bits, no parity-bit, one stop-bit, and a DTE rate
of 2400 bps.
Check DTE Connection
Check the DTE interface connection. Be sure the
CTS (Si24xx pin 7) signal is low.
Check pullup/pulldown configuration resistor.
Inappropriate Commands
Verify that all AT commands used are supported by
the Si24xx and comply with the proper format. Be
sure the command and argument are correct. Do not
mix uppercase and lowercase alphabetic characters
in an AT command (except the “r”, “m”, “q”, and “w”
commands).
Command Timing
The execution time for an AT command is
approximately 200 ms. Execution is complete when
the “O” is received. Subsequent AT commands
should wait for the “O” message, which appears
within 100 ms after the carriage return. The reset
recovery time (the time between a hardware reset or
the carriage return of an ATZ command and the time
the next AT command can be executed) is
approximately 100 ms. When a data connection is
being established, do not try to escape to the
command mode until after the protocol message.
Si3008 and/or Associated Components
If the modem goes off-hook and draws loop current
as a result of giving the ATH1 command, go to the
indicates
the
host
processor/software
DD
(3.3 V) in
is