PXB4219 Datasheet, PDF (82/290 Pages) Infineon Technologies AG – IWE8 Interworking Element for 8 E1/T1 Lines

PXB4219 / PXB4220 / PXB4221
Operational Description
4.7
OAM Processing
The OAM processing block (OM) will read Statistics Counter events from the Event
Queue as long as the Event Queue is not empty. The OM will read the Statistics Counter
value “count_value” and the Statistics Counter threshold from external RAM. If the
Statistics Counter is not yet at its maximum value 4000 0000_H, the value is increased
with the increment value given by the counter event. If the Statistics Counter threshold
is active (“thres_act” = 1) and the Statistics Counter equals or exceeds the threshold
value “thres_value”, the OM block will write an interrupt entry in the Interrupt Queue in
external RAM. The new Statistics Counter value with indication whether an interrupt was
generated in the “int_gen” field will finally be written into external RAM.
The “dest_read” bit determines whether a read operation from the microprocessor in the
Statistics Counter address space in external RAM causes a reset of the Statistics
Counter value.
The OM block can be disabled via bit “oam_act” in the OAM control register (“oamc”, see
Chapter 7.3).
In normal operation, counter event processing should be activated (oam_act = 1). In this
case the microprocessor can only read indirectly in the Interrupt Queue.
For RAM test and initialization, the “oam_act” should be set to 0. In this mode, the
microprocessor can write and read the complete external RAM.
The use of the Statistics Counter thresholds allows the software to reduce the number
of generated interrupts and to decide at what error level an interrupt should be
generated.
When the software wants to use polling mode, the thresholds can be made inactive, and
no interrupts will be generated. The software will read all the Statistics Counters on
regular time intervals in this mode.
A combination of both methods is also possible, all the Statistics Counters are read and
reset on regular time intervals. However thresholds can be used as an extra guard: a
Statistics Counter that reaches an exceptionally high value will cause an interrupt.
For a detailed list of all implemented Statistics Counters refer to Chapter 6.2.1. For
information how to translate Statistics Counters into the ATM Forum CES MIB as defined
in [10] refer to Chapter 8.2.
Data Sheet
82
2002-05-06