MT90220
3 UTOPIA Ports
(UNI)
(3 Links in UNI Mode)
ATM
Layer
Device
1 UTOPIA Port
(IMA Group #1)
(3 links)
(2 links)
Framer
8
1 UTOPIA Port
(IMA Group #2)
Figure 17 - ATM Mixed-Mode Interface to One MT90220
•
the total number of ICP cells sent through the
PCM link
6.0 Support Blocks
6.1 Counter Block
6.1.3 Receive PCM I/F Counters
The MT90220 includes 112 24-bit counters to
provide statistical information on the device’s
operation. All the counters are cleared by a hardware
reset. A maskable interrupt can be generated when
the counter overflows.
There are four counters associated with each of the
eight receive PCM links for a total of 32 Receive
counters. These counters record the following
information and are active as soon as the RX PCM
port is enabled:
•
the total number of cells received through the
PCM link or total number of Stuff events
received on the link (option selected in RX Link
Control registers)
A predetermined value can also be loaded in a
counter. This feature can be used to generate an
interrupt after a specified number of cells is
processed. Counter values are incremented by 1 for
every event occurrence and, when the count goes to
all 1’s, will overflow (to all 0’s).
•
•
•
the total number of Idle/Filler cells received
through the PCM link, , with good or bad HEC
the total number of ICP Cells with violation
received through the PCM link
6.1.1 UTOPIA Input I/F counters
There are four counters associated with the each of
the 12 UTOPIA Inputs (from ATM layer to the
MT90220) for a total of 48 counters. These counters
record the following information:
the total number of cells with wrong HEC
received through the PCM link but not including
the cells where the HEC is corrected
•
•
•
•
the total number of cells received at the
UTOPIA Input I/F
6.1.4 Access to the Counters
Accessing (READ) counters is a three step function.
First, the desired counter must be selected by writing
to the Counter Select Register. Second, the READ
command (’0x00x101’) is written to the Counter
Transfer Command register. This command causes
the current three byte count value to be copied from
the specified counter to the three byte-wide Counter
Bytes registers (note that this value is unchanged
until another counter read command is issued). And
third, the Counter Bytes registers are read to obtain
the three byte count value of the selected counter.
the total number of Idle Cells received at the
UTOPIA Input I/F, removed or not
the total number of Unassigned Cells received
at the UTOPIA Input I/F, removed or not
the number of cells having a single or multiple
bit error in the HEC, removed or not but not
including the cells where the HEC is corrected
6.1.2 Transmit PCM I/F Counters
There are four counters associated with the each of
the eight transmit PCM links for a total of 32 Transmit
counters. These counters record the following
information:
Pre-loading (WRITE) a counter is also a three step
function. First, the three byte, pre-load value, is
written to the three byte-wide Counter Bytes
registers. Second, the identification of the counter to
be pre-loaded is written to the Counter Select
Register. And third, the WRITE command
(’0x00x001’) is written to the Counter transfer
Command register.
•
•
•
the total number of cells sent through the PCM
link
the total number of Idle/Filler cells sent through
the PCM link
the total number of Stuff cells sent through the
PCM link
33
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