Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 5)

Si2493/57/34/15/04
Global ISOmodem-EVB
Rev. 0.6 5
current, and respond with an “OK.” Next, type
“ATH<cr>” or “ATH0<cr>”, and the modem should hang
up (go on-hook) and stop drawing loop current.
To make a modem connection, type “ATDT(called
modem phone number)<cr>.” Once the connection is
established, a “CONNECT” message appears indicating
the two modems are in the data mode and
communicating. Typing on one terminal should appear
on the other terminal. To return to the command mode
without interrupting the connection between the two
modems, type “+++.” Approximately two seconds later,
“OK” appears. The modem is now in command mode
and accepts “AT” commands.Type “ATH” (or “ATH0”) to
terminate the data connection, or type “ATO” to return to
the data mode. After the ATO command, the modem
resumes the data connection and no longer accepts AT
commands.
1.7. EVB Part Numbers
The ISOmodem evaluation boards are offered in
multiple speeds and packaging options. The first four
numbers indicate the system-side device. The next two
letters indicate the system-side package (FS–Lead-free,
16-pin SOIC; FT–Lead-free, 24-pin TSSOP). The final
two numbers indicate the line-side device. See Figure 5.
Figure 5. EVB Part Number Example
2. Si2493/57/34/15/04-EVB
Functional Description
The Si2493/57/34/15/04-EVB is a multipurpose
evaluation system. The modem daughter card
illustrates the small size and few components required
to implement an entire controller-based modem with
global compatibility. The daughter card can be used
independently of, or in conjunction with, the
motherboard. The motherboard adds features that
enhance the ease of evaluating the many capabilities of
the Si2493/57/34/15/04 ISOmodem
®
.
2.1. Motherboard
The motherboard provides a convenient interface to the
Si2493/57/34/15/04 DC (daughter card). The versatile
power supply allows for a wide range of ac and dc
voltages to power the board. RS-232 transceivers and a
DB9 connector allow the Si2493/57/34/15/04-EVB to be
easily connected to a PC or other terminal device.
Jumper options allow direct access to the LVCMOS/TTL
level serial inputs to the Si2493/57/34/15/04, bypassing
the RS-232 transceivers or USB interface. This is
particularly useful for directly connecting the Si2493/57/
34/15/04 to embedded systems.
The Si24xxURT-EVB motherboard connects to the
daughter card through two connectors, JP1 and JP2.
JP1 is an 8x2 socket providing connection to all Si2493/
57/34/15/04 digital signals and regulated 3.3 V power
for the Si2493/57/34/15/04. The Si2493/57/34/15/04
digital signals appearing at JP1 (daughter card
interface) are LVCMOS and TTL compatible. The
Si2493/57/34/15/04 daughter card must be powered by
3.3 V. The motherboard is factory configured for 3.3 V
with JP7. JP2 is a 4x1 socket providing connection
between the daughter card and the RJ-11 phone jack.
2.1.1. Voltage Regulator/Power Supply
The input voltage to either J3 or J4 must be between 7.5
and 13.5 V dc or 7.5 and 13.5 V
PEAK
ac. The
motherboard includes a diode bridge (D1–D4) to guard
against a polarity reversal of the dc voltage or to rectify
an ac voltage. The power source must be capable of
continuously supplying at least 100 mA. C6 serves as a
filter cap for an ac input. The voltage regulator, U1,
provides 5 V for the motherboard and the input for
voltage regulator U2, which outputs 3.3 V for use on the
motherboard and to power the daughter card. Si24xxDC
power consumption can be measured by placing a
meter between pins 1 and 2 of JP7. The connection
between JP7 pins 1 and 2 must be made at all times
when power is applied to the evaluation board either
through a jumper block or a low-impedance meter to
avoid damage to the daughter card. Power is supplied
to U2 through D5 from the USB.
2.1.2. Reset Circuitry
The Si2493/57/34/15/04 requires a reset pulse to
remain low for at least 5.0 ms after the power supply
has stabilized during the powerup sequence or for at
least 5.0 ms during a power-on reset. Most production
Si2493/57/34/15/04 modem chipset applications require
that RESET be controlled by the host processor. Certain
Si2493/57/34/15/04 operation modes, including
powerdown, require a hardware reset to recover.
The Si2493/57/34/15/04-EVB contains two reset
options, an automatic power-on reset device, U3
(DS1818) (default), and a manual reset switch (S1) to
permit resetting the chip without removing power. A
reset, regardless of the mechanism, causes all modem
settings to revert to factory default values. See
Si2457FS18-EVB
LS Part Number (Si30xx)
SS Package
SS Part Number