RELEASED
PM7383 FREEDM-32A256
DATASHEET
PMC-2010336
ISSUE 1
FRAME ENGINE AND DATA LINK MANAGER 32A256
more bandwidth per link for applications requiring higher data densities on a
single link. Data at each time-slot may be independently assigned to be sourced
from a different channel. Second, H-MVIP links reference the start of each frame
with a frame pulse, thereby avoiding having to gap the link clock during the
framing bits/bytes of each frame. The frame pulse is provided by an H-MVIP bus
master and ensures that all agents sharing the H-MVIP bus remain synchronized.
When configured for operation in 2.048 Mbps H-MVIP mode, the frame pulse is
sampled using the same clock which samples the data. When configured for
operation in 8.192 Mbps H-MVIP mode, the frame pulse is sampled using a
separate frame pulse clock provided by an H-MVIP bus master. The frame pulse
clock has a synchronous timing relationship to the data clock. Third, not all links
are independent. When configured for operation in 2.048 Mbps H-MVIP mode,
each group of 8 links share a clock and a frame pulse. Links 0 through 7, 8
through 15, 16 through 23 and 24 through 31 each share a clock and a frame
pulse. Not all 8 links within each group need to be configured for operation in
2.048 Mbps H-MVIP mode. However, any link within each logical group of 8
which is configured for 2.048 Mbps H-MVIP operation will share the same clock
and frame pulse. When configured for operation in 8.192 Mbps H-MVIP mode,
links 4m (0?m?7) share a frame pulse, a data clock and a frame pulse clock.
Again, not all eight 4m (0?m?7) links need to be configured for operation in 8.192
Mbps H-MVIP mode, however, any link which is configured for 8.192 Mbps H-
MVIP operation will share the same frame pulse, data clock and frame pulse
clock. If link 4m is configured for 8.192 Mbps H-MVIP operation, then data
transferred on that link is “spread” over links 4m, 4m+1 4m+2 and 4m+3 from a
channel assigner point of view. Accordingly, when link 4m is configured for
operation in 8.192 Mbps H-MVIP mode, links 4m+1, 4m+2 and 4m+3 must also
be configured for operation in 8.192 Mbps H-MVIP mode. In the back end, the
TCAS256 extracts and processes the time-slots identically to channelised
T1/J1/E1 traffic.
Links containing a T1/J1 or an E1 stream may be channelised. Data at each
time-slot may be independently assigned to be sourced from a different channel.
The link clock is only active during time-slots 1 to 24 of a T1/J1 stream and is
inactive during the frame bit. Similarly, the clock is only active during time-slots 1
to 31 of an E1 stream and is inactive during the FAS and NFAS framing bytes.
The most significant bit of time-slot 1 of a channelised link is identified by noting
the absence of the clock and its re-activation. With knowledge of the transmit
link and time-slot identity, the TCAS256 performs a table look-up to identify the
channel from which a data byte is to be sourced.
Links may also be unchannelised. Then, all data bytes on that link belong to one
channel. The TCAS256 performs a table look-up to identify the channel to which
PROPRIETARY AND CONFIDENTIAL
61
PMC [ PMC-SIERRA, INC ]
