SI3011-F-FSR Silicon Laboratories Inc, SI3011-F-FSR Datasheet - Page 44

• Manufacturer Part Number: SI3011-F-FSR
• Manufacturer: Silicon Laboratories Inc

Specifications of SI3011-F-FSR

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Si3050 + Si3011
5.36. GCI Highway
The Si3050 contains an alternate communication
interface to the SPI and PCM highway control and data
interface. The general circuit interface (GCI) can be
used for the transmission and reception of control and
data information onto a GCI highway bus. The PCM and
GCI highways are 4-wire interfaces and share the same
pins. The SPI control interface is not used as a
communication interface in the GCI highway mode, but
rather as hardwired channel selector pins.
When GCI mode is selected, the sub-frame selection
pins must be tied to the correct state to select one of
eight sub-frame timeslots in the GCI frame (Table 21).
These pins must remain in this state when the Si3050 is
operating. Selecting a particular subframe automatically
causes that individual Si3050 to transmit and receive on
the appropriate sub-frame in the GCI frame, which is
initiated by an FSYNC pulse. No more register settings
are needed to select which sub-frame a device uses,
and the sub-frame for a particular device cannot be
changed when in operation. Only one Si3050 DAA can
be assigned per sub-frame, which allows a total of eight
DAAs to be connected to the same GCI highway bus.
GCI mode supports a 1x and a 2x PCLK rate as shown
in Figures 5 and 6 on pages 13 and 14, respectively.
The PCLK rate is autodetected and no internal register
settings are needed to support either 1x or 2x PCLK
mode.
The GCI highway requires either a 2.048 or 4.096 MHz
clock frequency on the PCLK pin, and an 8 kHz frame
sync input on the FSYNC pin. The overall unit of data
used to communicate on the GCI highway is a frame,
which is 125 µs in length. Each frame is initiated by a
pulse on the FSYNC pin and the rising edge signifies
44
GCI Subframe 0 Selected
(Voice channels 1–2)
GCI Subframe 1 Selected
(Voice channels 3–4)
GCI Subframe 2 Selected
(Voice channels 5–6)
GCI Subframe 3 Selected
(Voice channels 7–8)
GCI Subframe 4 Selected
(Voice channels 9–10)
GCI Subframe 5 Selected
(Voice channels 11–12)
GCI Subframe 6 Selected
(Voice channels 13–14)
GCI Subframe 7 Selected
(Voice channels 15–16)
Table 21. GCI Mode Sub-Frame Selection
SDI_THRU SDO
1
1
1
1
0
0
0
0
1
1
0
0
1
1
0
0
CS
1
0
1
0
1
0
1
0
Rev. 1.11
the beginning of the next frame. In 2x PCLK mode,
there are twice as many PCLK cycles during each
125 µs frame versus 1x PCLK mode. Each frame
consists of eight fixed timeslot sub-frames that are
assigned using the Sub-Frame Select pins as described
in Table 18 on page 34 (SDI_THRU, SDO, and CS).
Within each sub-frame are four channels (bytes) of
data, including the two voice data channels (B1 and
B2), one Monitor channel (M) for initialization and setup
of the device, and one Signaling and Control channel
(SC) for communicating status of the device and for
initiating commands. Within the SC channel are six
Command/Indicate (C/I) bits and two handshaking bits
(MR and MX). The C/I bits are used for status and
command communication, whereas the handshaking
bits Monitor Receive (MR) and Monitor Transmit (MX)
are used for data exchanges in the Monitor channel.
Figure 41 illustrates the contents of a GCI highway
frame.
5.37. Companding in GCI Mode
The Si3050 supports µ-Law and A-Law companding
formats in addition to 8-bit or 16-bit linear data. The 8-bit
companding
Companding in PCM Mode" on page 37 and are shown
in Table 19 and Table 20. If 16-bit linear mode is used,
the resulting 16-bit samples are transmitted in both the
B1 and B2 channels of a single subframe. For proper
operation, select all Si3050 DAAs to use the B1 channel
with only one DAA per subframe.
5.38. 16 kHz Sampling Operation in GCI
The Si3050 can be configured to support a 16 kHz
sampling rate (as described in "5.34. 16 kHz Sampling
Operation in PCM Mode" on page 37) and transmit the
data on an 8 kHz GCI Highway bus. If 8-bit samples are
used with a 16 kHz sample rate, the samples are
transmitted in both the B1 and B2 channels of a single
subframe. If 16-bit linear mode is used, the resulting
16-bit samples are transmitted in both the B1 and B2
channels of two consecutive subframes. In this case,
assign one DAA per two subframes.
5.39. Monitor Channel
The Monitor channel is used for initialization and setup
of the Si3050. It also can be used for general
communication with the Si3050 by allowing read and
write access to the Si3050’s registers. Use of the
monitor channel requires manipulation of the MR and
MX handshaking bits, located in bits 1 and 0 of the SC
channel described below. For purposes of this
specification, “downstream” is identified to be the data
sent by a host to the Si3050. “Upstream” is identified to
be the data sent by the Si3050 to a host.
Mode
schemes
are
described
in
"5.33.