SI3008-B-FS Silicon Laboratories Inc, SI3008-B-FS Datasheet - Page 13

• Manufacturer Part Number: SI3008-B-FS
• Description: IC ISOMODEM FCC LINE-SIDE 8SOIC
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3008-B-FS

• Data Format: V.22, V23, V.32, V.34, V.90, Bell 103, Bell 212A
• Baud Rates: 56k
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Product: Modem Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

As shown in Figure 3, 8-bit and 9-bit data modes refer to
the DTE format over the UART. Line data formats are
configured through registers S07 (MF1) and S15 (MLC).
If the number of bits specified by the format differs from
the number of bits specified by the DCE data
communications equipment or line (DTE) format, the
MSBs are either dropped or bit-stuffed, as appropriate.
For example, if the DTE format is 9 data bits (9N1) and
the line data format is 8 data bits (8N1), the MSB from
the DTE is dropped as the 9-bit word is passed from the
DTE side to the DCE (line) side. In this case, the
dropped ninth bit can then be used as an escape
mechanism. However, if the DTE format is 8N1 and the
line data format is 9N1, an MSB equal to 0 is added to
the 8-bit word as it is passed from the DTE side to the
DCE side.
The Si2401 UART does not continuously check for stop
bits on the incoming digital data. Therefore, if the TXD
pin is not high, the RXD pin may echo meaningless
characters to the host UART. This requires the host
UART to flush its receiver FIFO upon initialization.
Data Format: SE0[3] (ND)
Data Rate: SE0[2:0] (SD)
Table 10. Modem Configuration Examples
DTE Interface
RXD
V.23 (1200 tx, 75 rx)
V.23 (75 tx, 1200 rx)
TXD
V.23 (600 tx, 75 rx)
V.23 (75 tx, 600 rx)
Modem Protocol
(S07[7] (HDEN) = 0, S07[6] (BD) = 0)
Figure 3. Link and Line Data Formats
Bell 212A
Bell 103
V.22bis
V.22
V.21
Si2401
Register S07 Values
Si3008
DCE (Line) Interface
Data Format: S15 (MLC)
Data Rate: S07 (MF1)
0x06
0x02
0x03
0x00
0x01
0x14
0x24
0x10
0x20
RJ11
Rev. 1.1
4.2.1. Command/Data Mode
Upon reset, the modem is in command mode and
accepts AT-style commands. An outgoing modem call
can be made using the “ATDT#” (tone dial) or “ATDP#”
(pulse dial) command after the device is configured. If
the handshake is successful, the modem responds with
the “c”, “d”, or “v” string and enters data mode. (The
byte following the “c”, “d”, or “v” is the first data byte.) At
this point, AT-style commands are not accepted. There
are three methods that may be used to return the
Si2401 to command mode:
Whether using an escape method or not, when the
carrier is lost, the modem automatically returns to
command mode and reports “N”.
4.2.2. 8-Bit Data Mode (8N1)
8-bit data mode is the default mode after powerup or
reset and is set by SE0[3] (ND) = 0
full duplex, and uses a total of 10 bits including a start
bit (logic 0), eight data bits, and a stop bit (logic 1). Data
received from the remote modem is transferred from the
Si2401 to the host on the RXD pin. Data transfer to the
host begins when the Si2401 asserts a logic 0 start bit
on RXD. Data is shifted out of the Si2401 LSB first at
the DTE rate determined by the SE0[2:0] (SD) setting
and terminates with a stop bit. Data from the host for
transmission to the remote modem is shifted to the
Si2401 on TXD beginning with a start bit, LSB first at the
DTE rate determined by the SE0[2:0] setting and
terminates with a stop bit.
Use the ESC pin—To program the GPIO3 pin to
function as an ESCAPE input, set GPIO3
SE2[5:4] = 11. In this setting, a positive edge
detected on this pin returns the modem to command
mode. The “ATO” string can be used to reenter data
mode.
Use 9-bit data mode—If 9-bit data format with
escape is programmed, a 1 detected on bit 9 returns
the modem to command mode. (See Figure 2 on
page 8.) This is enabled by setting SE0[3] (ND) = 1
and S15[0] (NBE) = 1. The ATO string can be used
to reenter data mode. Ninth bit escape does not
work in the security modes.
Use “+++”—The escape sequence is a sequence of
three escape characters that are set in S-register
S0F (“+” characters by default). If the ISOmodem
chipset detects the “+++” sequence and detects no
activity on the UART before or after the “+++”
sequence for a time period set by S-register S10, it
returns to command mode. To disable this escape
sequence, set S-register S10=FF. To remove the
time-dependent behavior, set S-register S10=00.
Si2401/Si3008
b
. It is asynchronous,
®
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