Motorola MPC8260 - Manual (Page 814)

29-34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
Counters are implemented in the dual-port RAM for each PHY device. The counters of
each PHY are located in the UNI statistics table, described in Section 29.10.7, ÒUNI
Statistics Table.Ó
29.9 ATM-to-TDM Interworking
The MPC8260 supports ATM and TDM interworking. The MCCs and their corresponding
SIs handle the TDM data processing. (See Chapter 27, ÒMulti-Channel Controllers
(MCCs),Ó and Chapter 14, ÒSerial Interface with Time-Slot Assigner.Ó) The ATM controller
processes the ATM data.
Possible interworking applications include the following:
¥ Circuit emulation service (CES)
¥ Carrying voice over ATM
¥ Multiplexing several low speed services, such as voice and data, onto one ATM
connection
Data forwarding between the ATM controller and an MCC can be done in two ways:
¥ Core intervention. When an MCC receive buffer is full and its RxBD is closed, the
MCC interrupts the core. The core copies the MCCÕs receive buffer pointer to an
ATM TxBD and sets the ready bit (TxBD[R]). Similarly, when an ATM receive
buffer is full and its RxBD is closed, the core services the ATM controllerÕs interrupt
by copying the ATM receive buffer pointer to an MCC TxBD and setting TxBD[R].
This mode is useful when additional core processing is required.
¥ Automatic data forwarding. This mode enables automatic data forwarding between
AAL1/AAL0 and transparent mode over a TDM interface.
29.9.1 Automatic Data Forwarding
The basic concept of automatic data forwarding is to program the ATM controller and the
MCC to process the same BD table, as shown in Figure 29-21.