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QuadFALC
TM
PEF 22554 E
Functional Description E1
Data Sheet
140
Rev. 1.2, 2006-01-26
4.3.5.4
Parallel Transmit CAS (E1)
The CAS information is taken from the registers XS(16:1) (XS1_E) and is transmitted on a multiframe boundary
in time slot 16. So the CAS information is controllable by the micro controller over the asynchronous, the SPI or
the SCI interface. The signaling controller inserts the bit stream on the transmit line side.
If the QuadFALC
TM is configured for no signaling, the system interface data stream passes the QuadFALCTM
undisturbed.
4.4
Framer Operating Modes (E1)
4.4.1
General (E1)
The general parameters are
The operating mode of the QuadFALC
TM is selected by programming the carrier data rate and characteristics, line
code, multiframe structure, and signaling scheme.
The QuadFALC
TM implements all of the standard framing structures for E1 or PCM 30 (CEPT, 2.048 Mbit/s)
carriers. The internal HDLC or CAS controller supports all signaling procedures including signaling frame
synchronization/synthesis and signaling alarm detection in all framing formats. The time slot assignment from the
PCM line to the system highway and vice versa is performed without any changes of numbering (TS0
TS0, …,
TS31
TS31).
Summary of supported E1 Framing Modes
Doubleframe format according to ITU-T G. 704
Multiframe format according to ITU-T G. 704
CRC4 processing according to ITU-T G. 706
Multiframe format with CRC4 to non CRC4 interworking according to ITU-T G. 706
Multiframe format with modified CRC4 to non CRC4 interworking
Multiframe format with CRC4 performance monitoring
After reset, the QuadFALC
TM is switched into doubleframe format automatically. Switching between the framing
formats is done by programming bits FMR2.RFS(1:0) and FMR3.EXTIW for the receiver and FMR1.XFS for the
transmitter.
4.4.2
Doubleframe Format (E1)
The framing structure is defined by the contents of time slot 0 (refer to Table 36).
Bit: FMR1.PMOD
:
0
PCM line bit rate
:
2.048 Mbit/s
Single frame length
:
256 bit, No. 1…256
Framing frequency
:
8 kHz
HDLC controller
:
n x 64 kbit/s, n = 1 to 32 or m x 4 kbit/s, m = 1 to 8
Organization
:
32 time slots, No. 0…31 with 8 bits each, No. 1…8
Table 36
Allocation of Bits 1 to 8 of Time Slot 0 (E1)
Bit Alternate Number Frames
1
2
3
4
5
6
7
8
Frame Containing the
Frame Alignment Signal
S
i
0
11
011
1)
Frame Alignment Signal