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DS3171/DS3172/DS3173/DS3174
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Table 10-16. GPIO Port Alarm Monitor Select
GPIO(A/B)[3:0]
LINE LOS
DS3/E3 OOF
DS3/E3 LOF
DS3/E3 AIS
DS3/E3 RAI
DS3 IDLE
0000
X
0001
X
0010
X
0011
X
0100
X
0101
X
0110
0111
1000
1001
1010
1011
X X X
1100
1101
X X X
1110
X
X
1111
X X X X X X
10.4.5 Performance Monitor Counter Update Details
The performance monitor counters are designed to count at least one second of events before saturating to the
maximum count. There is a status bit associated with some of the performance monitor counters that is set when
the its counter is greater than zero, and a latched status bit that gets set when the counter changes from zero to
one. There is also a latched status bit that gets set on every event that causes the error counter to increment.
There is a read register for each performance monitor counter. The count value of the counter gets loaded into this
register and the counter is cleared when the update-clear operation is performed. If there is an event to be counted
at the exact moment (clock cycle) that the counter is to be cleared then the counter will be set to a value of one so
that that event will be counted.
The Performance Monitor Update signal affects the counter registers of the following blocks: the BERT, the DS3/E3
framer, the Line Encoder/Decoder.
The update-clear operation is controlled by the Performance Monitor Update signal (PMU). The update-clear
operation will update the error counter registers with the value of the error counter and also reset each counter.
The PMU signal can be created in hardware or software. The hardware sources can come from the one-second
counter or one of the general-purpose IO pins, which can be programmed to source this signal. The software
sources can come from one of the per-port control register bits or one of the global control register bits. When
using the software update method, the PMU control bit should be set to initiate the process and when the PMS
status bit gets set, the PMU control bit should be cleared making it ready for the next update. When using the
hardware update method, the PMS bit will be set shortly after the hardware signal goes high, and cleared shortly
after the hardware signal goes low. The latched PMS signal can be used to generate an interrupt for reading the
count registers. If the port is not configured for global PMU signals, the PMS signal from that port should be
blocked from affecting the global PMS status.