
XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
PRELIMINARY
REV. P1.0.1
282
(AIC Interrupt Enable) within the RxDS3 Interrupt En-
able 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 AIC In-
terrupt
Whenever the XRT74L73 Framer IC detects this in-
terrupt, it will do all of the following.
It will assert the Interrupt Request Output pin (INT)
by driving it "High".
It will set Bit 2 (AIC Interrupt Status), within the Rx
DS3 Interrupt Status Register, to “1”, as indicated
below.
Whenever the Terminal Equipment encounters this
interrupt, it should do the following.
It should continue to check the state of the AIC bit,
in order to see if this change is constant.
If this change is constant, then the user should con-
figure the XRT74L73 Framer IC to operate in the
M13 framing format, if the AIC bit-field is “0”.
Conversely, if the AIC bit-field is “1”, then the user
should configure the XRT74L73 Framer IC to oper-
ate in the C-bit Parity framing format.
4.3.6.2.7
If the Detection of P-Bit Error Interrupt is enabled,
then the XRT74L73 Framer IC will generate an inter-
rupt, anytime the Receive DS3 Framer block has de-
tected a P-bit error, within the incoming DS3 data
stream.
Enabling and Disabling the Detection of P-Bit Er-
ror Interrupt:
The Detection of P-Bit Error Interrupt can be enabled
or disabled by writing the appropriate value into Bit 0
The Detection of P-Bit Error Interrupt
RXDS3 INTERRUPT ENABLE REGISTER (ADDRESS = 0X12)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
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
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0
RXDS3 INTERRUPT STATUS REGISTER (ADDRESS = 0X13)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
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
RUR
RUR
RUR
RUR
RUR
RUR
RUR
RUR
0
0
0
0
0
1
0
0