ATM Transmission Convergence Layer
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
34-2 Freescale Semiconductor
Protocol-specific overhead bits may be discarded or routed to other controllers by the SI
Performing ATM TC layer functions (according to ITU-T I.432)
Transmit (Tx) updates are as follows:
Cell HEC generation
Payload scrambling using self synchronizing scrambler (programmable by the user)
Coset gener ation (programmable by the user)
Cell rate by inserting idle cells
Receive (Rx) updates are as follows:
Cell delineation using bit by bit HEC checking and programmable ALPHA and DELTA
parameters for the delineation state machine
Payload des crambling using self synchronizing scrambler (programmable by the user)
Coset r emoving (programmable by the user)
Filtering idle/unassigned cells (programmable by the user)
Perfor ming HEC error detection and single bit error correction (programmable by the user)
Generating los s of cell delineation status/interrupt (LOC / LCD)
Operates with FCC2 (UTOPIA 8)
Serial loop back mode
Cell echo mode
Supports both FCC transmit modes:
External rate mode—Idle cells are generated by the FCC (microcode) to control data rate
Internal rate mode (sub-rate)—FCC transfers only the data cells using the required data rate.
The TC layer generates idle/unassigned cells to maintain the line bit rate
Supports the TC layer and PMD (physical medium dependent) WIRE interface (according to the
ATM-Forum af-phy-0063.000)