
XRT7250
DS3/E3 FRAMER IC
á
REV. 1.1.1
224
value into Bit 1 (OOF Interrupt Enable) within the
RxDS3 Interrupt Enable Register, as illustrated below.
Setting this bit-field to “1” enables this interrupt. Con-
versely, setting this bit-field to “0” disables this inter-
rupt.
Servicing the Change of State on Receive OOF In-
terrupt
Whenever the XRT7250 Framer IC detects this inter-
rupt, it will do all of the following.
It will assert the Interrupt Request output pin (INT)
by driving this pin "Low".
It will set Bit 1 (OOF Interrupt Status), within the
RxDS3 Interrupt Status Register to “1”, as indicated
below.
Whenever the Terminal Equipment encounters a
Change in OOF on Receive Interrupt, then it should
do the following.
1. It should determine the current state of the OOF
condition. Recall, that this interrupt can gener-
ated, whenever the XRT7250 Framer declares or
clears the OOF defects. Hence, the user can
determine the current state of the OOF defect by
reading the state of Bit 4 (RxOOF), within the
RxDS3 Configuration & Status Registers, as illus-
trated below.
If OOF is TRUE.
1. It should transmit a FERF (Far-End Receive Fail-
ure) to the Remote Terminal Equipment. The
XRT7250 Framer IC automatically supports this
action via the FERF-upon-OOF feature.
2. It should transmit the appropriate FEAC Message
(per Bellcore GR-499-CORE), to the Remote Ter-
minal, indicating that a Service Affecting condi-
tion has been detected in the Local Terminal
Equipment.
if OOF is FALSE
1. It should cease transmitting a FERF (Far-End
Receive Failure) indicator to the Remote Terminal
Equipment. The XRT7250 Framer IC automati-
cally supports this action via the FERF-upon-
OOF feature.
RXDS3 INTERRUPT ENABLE REGISTER (ADDRESS = 0X12)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
CP Bit Error
Interrupt
Enable
LOS
Interrupt
Enable
AIS
Interrupt
Enable
Idle Interrupt
Enable
FERF
Interrupt
Enable
AIC
Interrupt
Enable
OOF
Interrupt
Enable
P-Bit Error
Interrupt
Enable
R/W
00
000
RXDS3 INTERRUPT STATUS REGISTER (ADDRESS = 0X13)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
CP-Bit Error
Interrupt
Status
LOS
Interrupt
Status
AIS
Interrupt
Status
Idle Interrupt
Status
FERF
Interrupt
Status
AIC
Interrupt
Status
OOF
Interrupt
Status
P-Bit Error
Interrupt
Status
RURRUR
RUR
RURRUR
00
000
010
RXDS3 CONFIGURATION & STATUS REGISTER (ADDRESS = 0X10)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
RxAIS
RxLOS
RxIdle
RxOOF
Reserved
Framing On
Parity
FSync
Algo
MSync
Algo
RO
RUR
00
000