
Advance Data Sheet
T7633 Dual T1/E1 3.3 V Short-Haul Terminator
May 1998
108
Lucent Technologies Inc.
Facility Data Link (FDL)
Data may be extracted from and inserted into the facility data link in SLC-96, DDS, ESF, and CEPT framing
formats. In CEPT, any one of the Sa bits can be declared as the facility data link by programming register
FRM_PR43 bit 0—bit 2. Access to the FDL is made through:
1.
2.
The FDL pins (RFDL, RFDLCK, TFDL, and TFDLCK). Figure 43 shows the timing of these signals.
The 64-byte FIFO of the FDL HDLC block. FDL information passing through the FDL HDLC section may be
framed in HDLC format or passed through transparently.
5-3910(F).cr.1
Figure 43. T7633 Facility Data Link Access Timing of the Transmit and Receive Framer Sections
In the ESF frame format, automatic assembly and transmission of the performance report message (PRM) as
defined in both ANSI T1.403-1995 and Bellcore’s TR-TSY-000194 Issue 1, 12—87 is managed by the receive
framer and transmit FDL sections. The ANSI T1.403-1995 bit-oriented data link messages (BOM) can be
transmitted by the transmit FDL section and recognized and stored by the receive FDL section.
Receive Facility Data Link Interface
Summary
A brief summary of the receive facility data link functions is given below:
1.
Bit-oriented message (BOM) operation.
The ANSI T1.403-1995 bit-oriented data link messages are
recognized and stored in register FDL_SR3. The number of times that an ANSI code must be received for
detection can be programmed from 1 to 10 by writing to register FDL_PR0 bit 4— bit 7. When a valid ANSI
code is detected, register FDL_SR0 bit 7 (FRANSI) is set.
HDLC operation.
This is the default mode of operation when the FDL receiver is enabled (register FDL_PR1
bit 2 = 1). The HDLC framer detects the HDLC flags, checks the CRC bytes, and stores the data in the FDL
receiver FIFO (register FDL_SR4) along with a status of frame (SF) byte.
HDLC operation with performance report messages (PRM).
This mode is enabled by setting register
FDL_PR1 bit 2 and bit 6 to 1. In this case, the receive FDL will store the 13 bytes of the PRM report field in the
FDL receive FIFO (register FDL_SR4) along with a status of frame (SF) byte.
Transparent operation.
Enabling the FDL and setting register FDL_PR9 bit 6 (FTM) to 1 disables the HDLC
processing. Incoming data link bits are stored in the FDL receive FIFO (register FDL_SR4).
2.
3.
4.
t8
t9
t9
t10
t11
t8: TFDLCK CYCLE =
t9: TFDL TO TFDLCK SETUP/HOLD = 40 ns
t10: RFDLCK CYCLE =
t11: RFDLCK TO RFDL DELAY = 40 ns
TFDLCK
TFDL
RFDLCK
RFDL
250
μ
s (ALL OTHER
MODES)
125
μ
s (DDS)
250
μ
s (ALL OTHER
MODES)
125
μ
s (DDS)