2.2 The ATM Transmission Convergence ...................................................................................................... 10
2.2.1 TX Cell Ram and TX FIFO Length ................................................................................................... 10
2.3 Parallel to Serial PCM Interface ............................................................................................................... 11
2.4 ATM Transmit Path in IMA Mode ............................................................................................................. 11
2.4.1 IMA Frame Length (M) ..................................................................................................................... 11
2.4.2 Position of the ICP Cell in the IMA Frame........................................................................................ 11
2.4.10 TX IMA Group Start-Up.................................................................................................................... 14
2.4.11 TX Link Addition ............................................................................................................................... 14
2.4.12 TX Link Deletion............................................................................................................................... 14
2.5 ATM Transmit Path in UNI Mode ............................................................................................................. 15
3.0 The ATM Receive Path................................................................................................................................. 15
3.1 Cell Delineation Function ......................................................................................................................... 15
3.2 De-Scrambling and ATM Cell Filtering ..................................................................................................... 16
3.3 ATM Receive Path in IMA Mode .............................................................................................................. 16
3.3.10.5 Measured Delay Between Links................................................................................................ 21
3.3.10.6 Incrementing/Decrementing the Recombiner Delay ................................................................. 21
3.3.11 RX IMA Group Start-Up ................................................................................................................... 21
3.3.12 Link Addition .................................................................................................................................... 22
3.3.13 Link Deletion .................................................................................................................................... 22
3.3.14 Disabling an IMA Group ................................................................................................................... 22
3.4 The ATM Receive Path in UNI ................................................................................................................. 22
4.0 Description of the PCM Interface................................................................................................................
4.1 Serial to Parallel (S/P) and Parallel to Serial (P/S) Converters ................................................................
4.2 PCM System Interface Modes..................................................................................................................
4.2.1 Mode 2 and 6: ST-BUS Interface for T1 ..........................................................................................
4.2.1.1 Detailed ST-BUS Spaced Mapping (3 of Every 4 Channels) ....................................................
5.1 ATM Input Port .........................................................................................................................................
5.2 ATM Output Port ......................................................................................................................................
5.3 UTOPIA Operation With a Single PHY.....................................................................................................
5.4 UTOPIA Operation with Multiple PHY ......................................................................................................
5.5 UTOPIA Operation in UNI Mode ..............................................................................................................
5.6 UTOPIA Operation in IMA Mode ..............................................................................................................
5.7 Examples of UTOPIA Operation Modes...................................................................................................
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MT90220
Table of Contents
6.0 Support Blocks.............................................................................................................................................
6.2.1 IRQ Master Status and IRQ Master Enable Registers.....................................................................
6.2.2 IRQ Link Status and IRQ Link Enable Registers..............................................................................
6.2.2.1 Bit 7 and 6 of IRQ Link 0 Status and IRQ Link 0 Enable Registers ..........................................
6.2.3 IRQ Link UNI Overflow and IRQ UTOPIA Input UNI Overflow Status Registers .............................
6.2.4 IRQ IMA Group Overflow Status and Enable Registers...................................................................
6.2.5 IRQ IMA Overflow Status and RX UTOPIA IMA Group FIFO Overflow Enable Registers ..............
6.3 Register and Memory Map .......................................................................................................................
6.3.1 Access to the Various Registers ......................................................................................................
6.3.2 Direct Access ...................................................................................................................................
6.3.4 Clearing of Status Bits......................................................................................................................
6.3.4.1 Toggle Bit ..................................................................................................................................
6.3.5 Test Modes ......................................................................................................................................