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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—HSS Coprocessor
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
740
Reference Number: 004US
By using the IxHssAcc API, the following settings should be considered when
configuring HSS interface for E1 operation:
• Frame size 256 bits (for E1).
• Frame sync simultaneous with first bit in first timeslot – TX frame offset and RX
frame offset should be set due to HSS logic, different values due to external device
can be accommodated.
• Select use of input/output TX/RX frame syncs.
• Select use of input/output clock, and clock speed.
• Select negative/positive clock for generating/sampling frame in transmit/receive.
• Select negative/positive clock for generating/sampling data in transmit/receive.
• Frame sync active level (high/low).
• MSb/LSb-first ordering for transmit and receive.
• Data polarity, maintain or invert.
• Select to not use FBit at frame start.
• Select value for idle timeslots on transmit and unused bit in 56k timeslots.
• Select buffer size.
• Configure lookup tables.
13.5.3
GCI
The HSS hardware has support to allow connection to a General Circuit Interface (GCI).
This interface is also sometimes referred to as an IOM (ISDN Oriented Modular)
interface. The HSS hardware supports two basic modes of operation for GCI protocol:
• Line-Card Mode
• Termination Mode
13.5.3.1
Line-Card Mode
The General Circuit Interface (also know as IOM) is a serial data stream consisting of
8000 frames, 4 slots per frame and each slot is a byte wide. It is used to exchange
Bearer channel data (PCM-coded voice) and control information.
Figure 175. E1 RX Frame, Externally Generated Frame Pulse
B4246-02
hss_rx_data
hss_rx_clock
hss_rx_frame
data1
data3
data2
data1
data256
data2
data255