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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Reference Number: 306262-004US
737
HSS Coprocessor—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
illustrates a typical T1 frame with active high frame sync (level) and a
posedge clock for generating data. If the frame pulse was generated with a negedge
clock, the frame pulse in
would be located one half clock space to the right.
The same location applies to the data when being generated on the negedge of the
clock.
In
and
, the FBit to be transmitted is stored in the HSS Transmit
FIFO. The HSS knows which time slot in the FIFO is holding the F Bit, as it knows from
the time slot counter and frame offset when the F Bit should be transmitted.
illustrate a typical T1 received frame with an active high frame sync (level)
and a positive edge clock for sampling data.
Figure 170. T1 TX Frame, HSS Generating Frame Pulse
B4238-02
hss_tx_frame _out_en
hss_tx_data_out
hss_tx_clock
hss_tx_frame_out
hss_tx_data_out _en
FBit
data1
data2
data 192
data 191
FBit
data1
Figure 171. T1 TX Frame Using External Frame Pulse
B4239-02
hss_tx_data_out
hss_tx_clock
hss_tx_frame
hss_tx_data_out_en
FBit
data1
data2
data3
data4
data5
data7
data8