
XRT86L30
SINGLE T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.1
Set the read-only Receive Red Alarm State bit of the Alarm and Error Status Register (AESR) to one indicat-
ing there is Red Alarm detected in the incoming DS1 frame.
Set the Receive Red Alarm State Change bit of the Alarm and Error Status Register to one indicating there is
a change in state of Red Alarm. This status indicator is valid until the Framer Interrupt Status Register is
read.
Reading this register clears the associated interrupt if Reset-Upon-Read is selected in Interrupt Control Regis-
ter (ICR). Otherwise, a write-to-clear operation by the microprocessor is required to reset these status indica-
tors.
The table below shows the Receive Red Alarm State Change status bits of the Alarm and Error Status Regis-
ter.
PRELIMINARY
231
The Receive Red Alarm State bit of the Alarm and Error Status Register (AESR), on the other hand, is a read-
only bit indicating there is Red Alarm detected in the incoming DS1 frame.
The table below shows the Receive Red Alarm State status bits of the Alarm and Error Status Register.
12.3 Y
ELLOW
A
LARM
The Alarm indication logic within the Receive Framer block of the XRT86L30 framer monitors the incoming
DS1 frames for Yellow Alarm condition. The yellow alarm is detected and declared according to the following
procedure:
1.
Monitor the occurrence of Yellow Alarm pattern over a 6 ms interval. A YEL valid flag will be posted on the
interval when Yellow Alarm pattern occurred during the interval.
2.
Each interval with a valid YEL flag increments a flag counter which declares YEL alarm when 80 valid
intervals have been accumulated.
3.
An interval without valid YEL flag decrements the flag counter. The YEL alarm is removed when the
counter reaches zero.
If Yellow Alarm condition is present in the incoming DS1 frame, the XRT86L30 framer can generate a Receive
Yellow Alarm State Change interrupt associated with the setting of Receive Yellow Alarm State Change bit of
the Alarm and Error Status Register to one.
To enable the Receive Yellow Alarm State Change interrupt, the Receive Yellow Alarm State Change Interrupt
Enable bit of the Alarm and Error Interrupt Enable Register (AEIER) has to be set to one. In addition, the Alarm
and Error Interrupt Enable bit of the Block Interrupt Enable Register (BIER) needs to be one.
ALARM AND ERROR STATUS REGISTER (AESR) (ADDRESS = 0X0B02H)
B
IT
N
UMBER
B
IT
N
AME
B
IT
T
YPE
B
IT
D
ESCRIPTION
2
Receive Red Alarm
State Change
RUR /
WC
0 - There is no change of Red Alarm state in the incoming DS1 payload data.
1 - There is change of Red Alarm state in the incoming DS1 payload data.
ALARM AND ERROR STATUS REGISTER (AESR) (ADDRESS = 0X0B02H)
B
IT
N
UMBER
B
IT
N
AME
B
IT
T
YPE
B
IT
D
ESCRIPTION
7
Receive Red Alarm
State
R
0 - There is no Red Alarm condition detected in the incoming DS1 payload data.
1 - There is Red Alarm condition detected in the incoming DS1 payload data.