MPC8280 datasheet(993/1386 Pages) FREESCALE

993 / 1386 page

ATM Controller and AAL0, AAL1, and AAL5

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

31-33

31.8

ATM Layer Statistics

ATM layer statistics can be used to identify problems, such as the line-bit error rate, that affect the UNI

performance. Statistics are kept in three 16-bit wrap-around counters:

•

UTOPIA error dropped cells count—Counts cells discarded due to UTOPIA errors: Rx parity

errors and short or long cells.

•

Misinserted dropped cell count—Counts cells discarded due to address look-up failure.

•

CRC10 error dropped cell count—Counts cells discarded due to CRC10 errors. (ABR only).

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 31.10.7, “UNI Statistics Table.”

31.9

ATM-to-TDM Interworking

The MPC8280 supports ATM and TDM interworking. The MCCs and their corresponding SIs handle the

TDM data processing. (See Chapter 29, “Multi-Channel Controllers (MCCs),” and Chapter 15, “Serial

Interface with Time-Slot Assigner.”) 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 MCC’s 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 controller’s 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.

31.9.1

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 31-21.

16-bit

4-bit

12-bit

16-bit

CAM data in field:

UEAD

PHY addr

VPI

VCI

015 16

31 32

Figure 31-20. External CAM Address in UDC Extended Address Mode

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