VSC6134
Datasheet
The following table lists the detection and clearing thresholds for various BER conditions.
Table 4.
Detection and Clearing Error Thresholds for Various BER in OC-192
BER
10–3
10–4
10–5
10–6
10–7
10–8
10–9
Detection
78742
7875
786
Clearing
7875
786
154
154
154
154
128
128
95
95
79
2.2.3
J0 Monitor
The section trace byte (J0) is used to transmit repetitively a fixed-length string (message) so that a
section receiver can verify its continued connection to the transmitter. The operation of the J0 monitor is
controlled by the J0 control register.
When J0_MODE = 0 (default) the incoming J0 bytes are compared with the bytes of the last valid J0
message.The received J0 bytes are stored in the received message memory. A J0 message is valid after it
is received if it is consistently repeated for the programmed number of repetitions, which is controlled
by the configuration bits J0_REPEAT[2:0] (010 default). After a new J0 message is validated, it then
overwrites the previous stored message in the valid message memory. When a new valid J0 message is
received, the status bit J0S is set and a microprocessor interrupt is generated if the interrupt mask bit
J0M = 0. After the message is validated if the J0 mismatch is detected, the status bit J0S is set, and an
interrupt can be generated if it is not masked by the bit J0M. The current state for the J0 message can be
monitored by the live bit J0L. The validated J0 message can be accessed using the microprocessor
interface by reading the valid message memory J0BYTE.
When J0_MODE = 1, the incoming J0 bytes are compared against the bytes of a user-programmable J0
message. The J0 message is programmed by writing to the valid message memory. When a mismatch is
detected, an interrupt is generated by setting the status bit J0S.
J0_LENGTH defines the length of J0 message. When equal to 0 (default), the J0 bytes from
16 consecutive frames are extracted; when equal to1, the J0 bytes from 64 consecutive frames are
extracted.
The control bits J0_PATTERN are used to define the start of J0 message. The J0 monitor block finds the
defined start byte and stores it in the first location of the memory. The following starting patterns are
supported by J0 monitor:
●
●
●
J0_PATTERN = 00: No starting pattern is defined. The start of the J0 message could be anywhere.
Note: This pattern type is not supported for J0_MODE = 1.
J0_PATTERN = 01 (default): SONET format for message start is used. The first byte in the J0
message follows a CR (0x0D) character followed by a LF (0x0A) character.
J0_PATTERN = 10: SDH format for message start is used. The first byte in the J0 message is the
byte with a 1 in the MSB.
58 of 438
VMDS-10185 Revision 4.0
July 2006
VITESSE [ VITESSE SEMICONDUCTOR CORPORATION ]
