PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 108

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Semiconductor Group
Single Bits
User access to the Single Bits (SB) channel is mode dependent.
In transmit direction there are five possible sources for setting (different) SB: MON-1
messages, MON-2 messages, MON-8 messages, the pins PS1 and PS2 and the state
machine. MON-1, MON-2 and pins PS1 and PS2 can be manipulated directly by the
user. Bits controlled by the state machine can not be manipulated by the user in a direct
way.
In the receive direction the SB are given via MON-1 and MON-2 messages. Several
filtering methods are available. For details see section 4.2.3, page 115.
Note 31: U-interface data is scrambled before it is send to the U-interface and
Note 32: The synchronization words (bits 1-18 of each U basic frame) are set by
Note 33: The CRC channel can not be accessed by the user. These bits are
4.2.1
Figures 46 and 47 below sketch how data can generally be accessed by the user.
Figure 46
Transmitter
2B+D
From IOM
or µP
(To U)
descrambled when they are received from the U-interface (see
"Scrambler / Descrambler", page 62).
the transceiver core and can not be manipulated by the user.
calculated and set by the transceiver core automatically (see "Cyclic
Redundancy Check (CRC)", page 64). However there are several
methods of monitoring CRC violations, which are discussed in detail in
chapter 4.5, page 176.
Data
Access to Data Channels of U-Interface
Access to Data Transmission on U
®
-2
Transmiter
FIFO
18 Bits
Fixed
(I)SW
12x (2B+D)
216 Bits
Data
108
U Basic Frame
1.5 ms
M1-M3
3 Bits
1 Bit
M4
Operational Description
M5-M6
2 Bit
Data Sheet 01.99
Time
PEB 2091
PEF 2091