PXB4219 Datasheet, PDF (48/290 Pages) Infineon Technologies AG – IWE8 Interworking Element for 8 E1/T1 Lines

PXB4219 / PXB4220 / PXB4221
Operational Description
• the receiver must subtract (equal to add modulo 2) the same pattern from the 8 HEC
bits before calculating the syndrome of the header.
As an example, if the first 4 octets of the header were all zeros the generated header
before scrambling would be “00000000_00000000_00000000_00000000_01010101”.
The starting value for the polynomial check is 0s (binary)
The coset value is programmable in the ATM Control Register (“atmc”, see
Chapter 7.8).
4.1.2 Setup of ATM Transmit Ports
Each ATM transmit port can be configured in the “channel_mode” field of the “ATM
Transmit Reference Slot” in RAM2 to operate in “Inactive”, “Active” or “Standby” mode.
In “Inactive” mode, byte-pattern 0 “bp0” is continuously sent to the framer transmit
interface.
In “Active” mode, user cells or idle/unassigned cells are sent to the framer transmit
interface.
In “Standby” mode, only idle/unassigned cells are sent to the framer transmit interface.
When activating ATM transmit ports, it is important to follow the initialization sequence
as shown in Table 13. Step 2 must be held at least 250 µs to internally reset the ATM
transmit port. During this time the device connected to the Framer Receive Interface has
to be in normal operation allowing the IWE8 to synchronize itself on the frame pulse.
Table 13 Activation sequence for ATM transmit ports
Step pcfN.
p_tx_act
ATM Transmit Reference Slot.
channel_mode
1
0 = inactive
00 = Inactive
2
1 = active
00 = Inactive
3
1 = active
01 or 11 = Active
Minimum Time
250 µs
Data Sheet
48
2002-05-06