SI3015-FS Silicon Laboratories Inc, SI3015-FS Datasheet - Page 27

• Manufacturer Part Number: SI3015-FS
• Description: SI2400 ISOMODEM LINE-SIDE
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3015-FS

• Data Format: V.90
• Interface: Serial
• Voltage - Supply: 3.3 V ~ 5 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Baud Rates: -

3. When the next frame of data is detected, EOFR is lowered
Fast Connect
In modem applications that require fast connection
times, it is possible to reduce the length of the
handshake.
If the Si2400 is set up as an answering modem, the
answer tone transmitted by the Si2400 may be
shortened by setting S1E (TATL) = 0x00 and setting
S34 (TASL) to the desired answer tone length. For the
most robust operation, it is recommended that the
answer tone sent by the answering modem be at least
10 msec (S34 (TASL) = 0x06).
If the Si2400 is configured as an originating modem,
setting the No Answer Tone bit (S33[1] [NAT] = 1b)
forces the Si2400 to recognize a short answer tone,
thereby reducing the overall connection sequence.
Additional modem handshaking control can be adjusted
through the registers shown in Table 16. These
registers are most useful if the user has control of both
the originating and answer modems.
(or bit 9)
configured as EOFR by setting SE4[3] (GPE) = 1b. In
addition to using the EOFR pin to indicate that the byte is a
frame result word, if in 9-bit data mode (set S15[0] (NBE) =
1b), the ninth bit will be raised if the byte is a frame result
word. To program this mode, set S0C[3] (9BF) = 1b and
SE0[3] (ND) = 1b.
and the process repeats at step 1.
EO FR
RXD
CTS
TXD
Si2400 ready for byte 1 of frame N
Start
Host begins frame N
Note: Figure not to scale.
Receive Data
Start
Stop
(CTS used as normal flow control.)
Start
Frame N
Figure 11. HDLC Timing
CRC Byte 1
A. Fram e Transm it
B. Fram e Receive
Rev. 1.1
Stop
To summarize, the host will begin receiving data
asynchronously from the Si2400. When each byte is
received, the host should check the EOFR pin (or the
ninth bit). If the EOFR pin (or the ninth bit) is low, then
the data is valid frame data. If the EOFR pin (or the
ninth bit) is high, then the data is a frame result word.
Host finished sending frame N
Start
Stop
Si2400 detects end of frame N.
CRC Byte 2
Si2400 ready for byte 1
of frame N + 1.
Stop
Host begins frame N + 1
Start
Start
Frame Result W ord
Si2400
Frame N + 1
Stop
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