Motorola PowerQUICC II MPC8280 Series Reference Manual page 1131

32.4.5 Trunk Condition
According to the Bellcore standard, the interworking function should be able to transmit
special payloads on both the ATM and TDM channels to signal alarm conditions (bellcore
TR-NWT-000170). The trunk condition can be generated under core control. The core may
deliver buffers containing special data (trunk condition payload) to the ATM controller or
MCC or even overwrite data buffers being used by the channels.
32.4.6 Channel Associated Signaling (CAS) Support
For applications requiring channel associated signaling (CAS) support, the CAS
manipulation is done by an external framer. The MCC should be programmed to receive or
transmit the internal CAS block transparently through the external framer's serial interface.
The internal CAS block (depicted in Figure 32-8) can be adjusted to comply with a specific
framer's serial interface. (See Section 32.4.7.1, "CAS Routing Table.")
8-bits per channel
Ch 1 Ch 2
XXXX ABCD
8-bits per channel
Ch 1 Ch 2
XXXX ABA'B'
8-bits per channel
Ch 1 Ch 2
XXXX ABCD
Note: The MCC should capture the signaling data on the last frame of a super frame.
See Section 1.4.7.2, "TDM-to-ATM CAS Support".
Figure 32-7. Mapping CAS Data on a Serial Interface
The MCC and ATM CAS are synchronized with the superframe block boundary. At the
ATM side, the structured block size should be set to the superframe block size plus the size
of the CAS block so that the structured pointer inserted by the ATM controller points to the
start of the structured data block. At the MCC side, the MCC is synchronized with the frame
sync signal; the external framer has the ability to place the signaling information at the
appropriate place in a superframe. The MPC8280 supports an automatic mode for
forwarding the signaling information from the TDM to the ATM and vice versa. The ATM
controller maintains two CAS blocks per trunk (eight total). One contains the signaling
MOTOROLA
Freescale Semiconductor, Inc.
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Ch 3
Framer serial interface for T1 signaling format
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Ch 3 • • • • • • • •
Framer serial interface for T1 signaling format (SF)
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Ch 3
Framer serial interface for E1 signaling format
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Chapter 32. ATM AAL1 Circuit Emulation Service
For More Information On This Product,
Go to: www.freescale.com
Ch 24
XXXX ABCD
Ch 24
XXXX ABA'B'
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Interworking Functions
Ch 32
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