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DS3/E3 FRAMER IC
XRT7250
REV. 1.1.1
63
cally, the Receive DS3 Framer will assert this bit-field
under either of the following two conditions:
1. When the Receive DS3 Framer detects the onset
of the Idle Condition and
2. When the Receive DS3 Framer detects the end
of the Idle Condition.
The local P can determine the current state of the
Idle condition by reading bit 5 of the Rx DS3 Configu-
ration and Status Register (Address = 0x10).
NOTE: For more information into the Idle Condition, please
see Section 3.3.2.5.3.
Bit 3 - FERF Interrupt Status
This Reset Upon Read bit will be set to '1' if the Re-
ceive DS3 Framer has detected a Change in the Rx
FERF Condition, since the last time this register was
read.
This bit-field will be asserted under either of the fol-
lowing two conditions.
1. When the Receive DS3 Framer first detects the
occurrence of an Rx FERF Condition (all X-bits
are set to '0').
2. When the Receive DS3 Framer detects the end
of the Rx FERF Condition (all X-bits are set to
'0').
The local microprocessor can determine the current
state of the FERF Condition by reading bit 4, within
the Rx DS3 Status Register (Address = 0x11).
NOTE: For more information on the Rx FERF (Yellow
Alarm) condition, please see Section 3.3.2.5.4.
Bit 2 - (Change in) AIC Interrupt Status
This Reset Upon Read bit-field is set to "1" if the AIC
bit-field, within the incoming DS3 frames, has
changed state since the last read of this register.
NOTE: For more information on this interrupt condition,
please see Section 3.3.2.5.6.
Bit 1 - OOF Interrupt Status
This Reset Upon Read bit-field is set to "1" if the Re-
ceive DS3 Framer has detected a Change in the Out-
of-Frame (OOF) Condition, since the last time this
register was read. Therefore, this bit-field will be as-
serted under either of the following two conditions:
1. When the Receive DS3 Framer has detected the
appropriate conditions to declare an OOF Condi-
tion.
2. When the Receive DS3 Framer has transitioned
from the OOF Condition (Frame Acquisition
Mode) into the In-Frame Condition (Frame Main-
tenance mode).
NOTE: For more information of the OOF Condition, please
see Section 3.3.2.2.
Bit 0 - P-Bit Error Interrupt Status
This Reset Upon Read bit-field indicates whether or
not the Detection of P-bit error interrupt has occurred
since the last read of this register. This bit-field will
be "0" if the Detection of P-bit error interrupt has NOT
occurred since the last read of this register. This bit-
field will be set to "1", if this interrupt has occurred
since the last read of this register. The Detection of
P-bit Error interrupt will occur if the Receive DS3
Framer Block detects a P-bit error in the incoming
DS3 frame.
NOTE: For more information into the role of P-bits please
see Section 3.3.2.6.1.
3.3.2.11 Receive DS3 Sync Detect Enable Register
RxDS3 Sync Detect Enable Register (Address =
0x14)
Bits 4 - 0 Enable5 F(4)- F(0)
These Read/Write bit-fields allows the user to enable
or disable the 5 parallel searches for valid M and F-
bit, while the Receive DS3 Framer is operating in the
Frame Acquisition mode. For proper operation, the
user is highly encouraged to ensure that all of these
bit-fields are set to "1".
RXDS3 SYNC DETECT ENABLE REGISTER (ADDRESS = 0X14)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
Not Used
Enable F[4]
Enable F[3]
Enable F[2]
Enable F[1]
Enable F[0]
RO
R/W
0
0011
111