cx28394 Conexant Systems, Inc., cx28394 Datasheet - Page 78

• Manufacturer Part Number: cx28394
• Description: Quad/x16/octal-t1/e1/j1 Framers
• Manufacturer: Conexant Systems, Inc.

2.0 Circuit Description
2.2 Receiver
2-20
2.2.10.2 RBOP Receiver
The Receive Bit-Oriented Protocol (RBOP) receiver receives BOP messages,
including the ESF Yellow Alarm, which consists of repeated 16-bit patterns with
an embedded 6-bit codeword as shown in this example:
selected by Data Link #1 [DL1_TS; addr 0A4]. It must be configured to operate
over the FDL channel so RBOP can detect priority, command, and response
codeword messages according to ANSI T1.403, Section 9.4.1.
Transceiver register [BOP; address 0A0]. BOP codewords are received in the
Receive BOP Codeword register [RBOP; addr 0A2], which contains the 6-bit
codeword, a valid flag (RBOP_VALID), and a lost flag (RBOP_LOST). The valid
flag is set each time a new codeword is put in RBOP, and is cleared on reading the
codeword. The lost flag indicates a new codeword overwrote a valid codeword
before being read by the processor.
filter and integration filter. The receive BOP message length filter [RBOP_LEN;
addr 0A40] sets the number of successive identical messages required before
RBOP is updated. RBOP_LEN can be set to 1, 10, or 25 messages. When
enabled, the RBOP integration filter [RBOP_INTEG; add 0A0] requires receipt
of two identical consecutive 16-bit patterns, without gaps or errors between
patterns, to validate the first codeword. RBOP integration is needed to meet the
codeword detection criteria while receiving 1/1000 bit error ratio.
RBOP_ACTIVE bit in the BOP Status register [BOP_STAT; addr 0A3]. Each
time a message is put in RBOP register, an interrupt is generated, and the RBOP
bit is set in the Data Link 2 Interrupt Status register [ISR1; addr 00A].
The BOP message channel is configured to operate over the same channel
RBOP is enabled using the RBOP_START bit in Bit Oriented Protocol
The BOP receiver can be configured to update RBOP using a message length
The real-time status of the codeword reception can be monitored using the
0xxxxxx0 11111111 (received right to left)
[543210] RBOP = 6-bit codeword
Conexant
Quad/x16/Octal—T1/E1/J1 Framers
CX28394/28395/28398
100054E