á
PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
245
The contents of these registers reflect the total num-
ber of BIP-8 Errors that have been detected since the
last read of these registers. These registers are reset
upon read.
7.2.2.2.2
The incoming G1 Byte serves to provide the “Near-End”
Terminal with diagnostic information on the quality of
the transmission link between the “Near-End” Transmit
PLCP Processor and the “Far-End” Receive PLCP
Processor. The bit-format of the G1 byte, presented
in Figure 69, indicates that 5 of the 8 bits in this byte
are relevant to transmission diagnosis.
G1 Byte
Bit 3—RAI—Yellow Alarm Indicator
This bit-field serves as a “Yellow Alarm” indicator.
The “Far-End” Transmit PLCP Processor will assert
this bit-field if the “Far End” Receive PLCP Processor
has had sufficient trouble receiving valid data from
the “Near-End” Transmit PLCP Processor; and that
this condition has persisted for 2 to 10 seconds. If
this bit-field is asserted for 10 consecutive incoming
PLCP frames then the Receive PLCP Processor will
assert the “Yellow Alarm” status bit (Bit 0) within the
Receive PLCP Configuration/Status Register, as
depicted below.
Bit 0, within the Receive PLCP Configuration Status
register will be negated when the Receive PLCP Pro-
cessor has received 10 consecutive G1 bytes with
the RAI bit-field being “0”.
Bits 4 through 7—FEBE
This nibble-field represents the number of “BIP-8” bit-
errors that were detected by the “Far-End” Receive
PLCP Processor in a given PLCP frame. Because of
the nature of the BIP-8 value, the FEBE nibble-field
can indicate as many as 8 bit-errors. If the “Near-End”
Receive PLCP Processor receives a G1 byte that
contains a non-zero FEBE value, then the “Near-
End” Receive PLCP Processor will increment the
PMON PLCP FEBE Count Register (Address = 2C,
2D) by the value of the FEAC nibble-field within the
received G1 byte. The bit-format of these registers is
presented below.
0
0
0
0
0
0
0
0
Address = 29h, PMON BIP-8 Error Count Register—LSB
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Rx PLCP Configuration/Status Register (Address = 44h)
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Unused
Reframe
POOF Status
PLOF Status
Yellow Status
x
x
x
x
x
x
x
1
Address = 2Ch, PMON PLCP FEBE Count Register—MSB
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
PFEBE Count—High Byte
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0
Address = 2Dh, PMON PLCP FEBE Count Register—LSB
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
PFEBE Count—Low Byte
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
0