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Intel
®
IXP42X Product Line of Network Processors and IXC1100 Control Plane Processor
September 2006 DM
Order Number: 252480-006US 459
High-Speed Serial Interfaces—Intel
®
IXP42X product line and IXC1100 control plane
processors
• Frame sync active level (high/low).
• MSb/LSb-first ordering for transmit and receive.
• Data polarity, maintain or invert.
• Select to use FBit (not data for T1) at frame start.
• Select value for idle timeslots on transmit and unused bit in 56k timeslots.
• Select buffer size.
• Configure lookup tables.
17.6.2 E1
E1 is a High-Speed Serial stream operating at 2.048 MHz. The stream is composed of
frames of which there are 8000 a second. Each frame consists of 32 slots, and each slot
is a byte in size. As there are 32 slots per frame, E1 can carry 32 channels. There are
no frame bits in this protocol.
Figure 88 and Figure 89 illustrate a typical E1 frame with an active high frame sync
(level) and a positive edge clock for generating or sampling data. The HSS clock and
frame pulse can be programmed to be either HSS outputs or HSS inputs. An offset can
be programmed indicating when the TX frame is to be transmitted. The Polarity of the
received data and the level of the frame can also be programmed using the IxHssAcc
API.
Figure 88. E1 Transmit Frame
hss_t x_dat a
hss_t x_cl ock
hss_t x_f r ame
data 1 data 2 data 3 data 256data 255 data 1 data 2