pxb4340e Infineon Technologies Corporation, pxb4340e Datasheet - Page 46

• Manufacturer Part Number: pxb4340e
• Description: Atm Oam Processor Aop
• Manufacturer: Infineon Technologies Corporation

The PXB 4340 AOP provides two types of cell filters:
• filters for special OAM cells
• filters for general purpose ATM cells
For both filter types two filters are provided.
For these filters only the first payload byte of the desired OAM cell (OAM type and function type
field) has to be programmed. The other criteria of OAM cells, VCI or PT coding are hard-wired
in the chip. All OAM cells, F4 and F5, segment and end-to-end are detected. The filters are
working for up- and downstream direction. For each filter the action upon the detection of an
OAM cell of the programmed type can be programmed:
• ignore cell (default)
• discard cell
• extract to receive buffer
• copy to receive buffer and forward.
Applications for this filter function are e.g. proprietary OAM functions using the standardized
System OAM cell coding or the treatment of future OAM cell types.
These filters consist of 3 programmable words for the comparison of all 5 cell header bytes plus
the first payload byte. The UTOPIA cell format described in
is compared. Each bit
can be individually masked with the mask pattern defined in 3 programmable mask registers. A
masked bit matches always when the pattern is compared to the ATM cells. Cells from both up-
and downstream direction are compared. Upon match the following actions can be selected:
• ignore cell (default); e.g. forward cell
• discard cell
• extract to receive buffer
• copy to receive buffer and forward.
See
for the receive buffer description.
In addition to the these actions the match signals of both comparators and for up- and
downstream direction are output at four pins as a short pulse. The pulses can be further
processed by external logic. This feature could be used for measurements.
Other applications for the general purpose cell filters are e.g. communication channels within a
switch or the filtering of RM cells.
A 16-bit microprocessor interface for embedded controllers like e.g. the 386EX is provided for
configuration and operation of the PXB 4340 AOP. 8 address lines allow to address 172
registers (non-contiguous addresses). Interrupts are provided for the notification of unexpected
events. DMA support is provided for fast data transfer to and from the external RAMs.
Data Sheet
2-46
04.2000