
á
XRT7250
DS3/E3 FRAMER IC
REV. 1.1.1
295
)
The Framer IC will respond to this command by doing
the following.
1. Asserting both the RxOOF and RxLOF output
pins.
2. Generating both the Change in OOF Status and
the Change in LOF Status interrupts to the Micro-
processor.
3. Asserting both the RxLOF and RxOOF bit-fields
within the Rx E3 Configuration & Status Register,
as depicted below.
5.3.2.4
Performance Monitoring of the Frame
Synchronization Section, within the Receive E3
Framer block
The user can monitor the number of FAS pattern er-
rors that have been detected by the Receive E3
Framer block. This is accomplished by periodically
reading the PMON Framing Bit/Byte Error Event
Count Registers (Address = 0x52 and 0x53). The
byte format of these registers are presented below.
5.3.2.5
The RxOOF and RxLOF output pin.
The user can roughly determine the current framing
state that the Receive E3 Framer block is operating in
by reading the logic state of the RxOOF and the Rx-
LOF output pins.
Table 61 presents the relationship
between the state of the RxOOF and RxLOF output
pins, and the Framing State of the Receive E3 Framer
block.
5.3.2.6
E3 Receive Alarms
5.3.2.7
The Loss of Signal (LOS) Alarm
Declaring an LOS Condition
The Receive E3 Framer block will declare a Loss of
Signal (LOS) Condition, when it detects 32 consecu-
tive incoming “0’s” via the RxPOS and RxNEG input
pins or if the ExtLOS input pin (from the XRT7300
DS3/E3/STS-1 LIU IC) is asserted. The Receive E3
Framer block will indicate that it is declaring an LOS
condition by.
I/O CONTROL REGISTER (ADDRESS = 0X01)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
Disable
TxLOC
LOC
Disable
RxLOC
AMI/
ZeroSup*
Unipolar/
Bipolar*
TxLine
Clk
Invert
RxLine
Clk
Invert
Reframe
R/W
RO
R/W
1
0100
001
RXE3 CONFIGURATION & STATUS REGISTER - 2 (ADDRESS = 0X11)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
RxLOF
Algo
RxLOF
RxOOF
RxLOS
RxAIS
Not Used
RxFERF
R/W
RORO
RO
RORORORO
0
1100
110
TABLE 61: THE RELATIONSHIP BETWEEN THE LOGIC STATE OF THE RXOOF AND RXLOF OUTPUT PINS, AND THE
FRAMING STATE OF THE RECEIVE E3 FRAMER BLOCK
RXLOF
RXOOF
FRAMING STATE OF THE RECEIVE E3 FRAMER BLOCK
00
In Frame
01
OOF Condition (The Receive E3 Framer block is operating in the 3ms OOF period).
10
Invalid
11
LOF Condition