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XRT79L71
PRELIMINARY
215
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
decremented, or kept at zero if a non-Idle M-frame is detected. The Receive DS3 Framer block will declare an
Idle Condition if this counter reaches the value of 63 M-frames or greater. Explained another way, the Receive
DS3 Framer block will declare an Idle Condition if the number of Idle-Pattern M-frames is detected such that it
meets the following conditions.
NIDLE - NVALID
63,
where:
NIDLE = the number of M-frames containing Idle Patterns
NVALID = the number of M-frames not exhibit the Idle Pattern
Anytime the contents of this Up/Down Counter reaches the number 63, then the Receive DS3 Framer block
will:
Set Bit 5 (RxIdle of the Receive DS3 Configuration and Status Register, as depicted below.
The Receive DS3 Framer block will also generate a Change in Idle Status interrupt request, by asserting the
Interrupt Output pin (e.g., by pulling it "Low") and setting Bit 4 (Idle Interrupt Status), within the Receive DS3
Interrupt Status Register, to "1" as illustrated below.
4.3.2.5.2
Clearing the Idle Condition
The Receive DS3 Framer block will clear the Idle Condition if it has detected a sufficient number of Non-Idle M-
frames, such that this Up/Down Counter reaches the value "0". The Receive DS3 Framer block will indicate
that it is clearing the Idle Condition by:
Setting Bit 5 of the (RxIdle Condition Declared) within the Receive DS3 Configuration and Status Register to
"0" as depicted below.
Receive DS3 Configuration and Status Register (Address = 0x1110)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
RxAIS
Defect
Declared
RxLOS
Defect
Declared
RxIdle
Condition
Declared
RxOOF
Defect
Declared
Unused
Framing with
Valid P-Bits
F-Sync Algo
M-Sync Algo
R/O
R/W
0
1
0
Receive DS3 Interrupt Status Register (Address =0x1113)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Detection of
CP Bit Error
Interrupt
Status
Change of
LOS Defect
Condition
Interrupt
Status
Change of
AIS Defect
Condition
Interrupt
Status
Change of
DS3 Idle
Condition
Interrupt
Status
Change of
FERF Defect
Condition
Interrupt
Status
Change of
AIC State
Interrupt
Status
Change of
OOF Defect
Condition
Interrupt
Status
Detection of
P-Bit Error
Interrupt
Status
RUR
0
1
0