FALC
56
PEF 2256 H/E
Functional Description E1
User’s Manual
Hardware Description
104
DS1.1, 2003-10-23
combination of S
a
-bits which shall be inserted in the outgoing data stream can be
selected by XC0.SA(8:4).
4.4.7.4
Channel Associated Signaling CAS (E1, serial mode)
In external signaling mode (serial mode) the signaling data received on port XSIG is
sampled with the working clock of the transmit system interface (SCLKX) in combination
with the transmit synchronization pulse (SYPX). Data on XSIG is latched in the bit
positions 5 to 8 per time slot, bits 1 to 4 are ignored. Time slots 0 and 16 are sampled
completely (bit 1 to 8). The received CAS multiframe is inserted frame aligned into the
data stream on XDI and must be valid during the last frame of a multiframe if
CRC4/multiframe mode is selected. The CAS multiframe is aligned to the
CRC4-multiframe; other frames are ignored. Data sourced by the internal signaling
controller (μP access mode) overwrites the external signaling data.
If the FALC
56 is configured for no signaling, the system interface data stream passes
the FALC
56 undisturbedly.
Note: CAS data on XSIG is read in the last frame of a multiframe only and ignored in all
other frames.
Figure 29
2.048 MHz Transmit Signaling Highway (E1)
4.4.7.5
Channel Associated Signaling CAS (E1, μP access mode)
Transmit data stored in registers XS(16:1) is transmitted on a multiframe boundary in
time slot 16. The signaling controller inserts the bit stream either on the transmit line side
or, if external signaling is enabled, on the transmit system side using pin function XSIG.
Data sourced by the internal signaling controller overwrites the external signaling data.
F0132
A B C D
A B C D
4 5 6 7
0 1 2 3 4 5 6 7
TS31
TS0
TS1
0 0 0 0 X Y X X
0 1 2 3 4 5 6 7
TS16
A B C D
0 1 2 3 4 5 6 7
TS31
XSIG
XDI
SCLKX
FAS/NFAS
FAS/NFAS
SYPX
T
125 μs
T
FAS
NFAS
ABCD
0000XYXX
= Time slot offset (XC0, XC1)
= Frame alignment signal, is taken from XSIG, not from XDI
= TS0 not containing FAS
= Signaling bits for time slots 1...15 and 17...31 of CAS multiframe
= CAS multiframe alignment signal, has to be provided in TS16