peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 85

• Manufacturer Part Number: peb20560
• Description: Dsp Oriented Pbx Controller Doc
• Manufacturer: Infineon Technologies Corporation

Table 2-12 Control Channel Delay Examples
System
Configuration
U
- U
U
- S
- S
U
- U
- U
S
- S
2.1.2.5.3
Depending on the selected system configuration different delays between the activation
of the control channel and the corresponding D-channel response occur.
Beware of Arbiter Locking!
In the state “limited selection”, the D-channel arbiter sends the “blocked” information to
the terminal from which the last HDLC-frame was received. Since the “blocked”
information reaches the terminal with several IOM-frames delay
5 × 125 µs) the terminal may already have started sending a second HDLC-frame. On
reception of the “blocked” information the terminal immediately aborts this frame.
Since the abort sequence of the second frame reaches the ELIC with several frames
delay
re-enters the state “full selection” only after the abort sequence of the second frame has
reached the ELIC.
If the D-channel arbiter re-enters the “full selection” state (in which it again sends an
“available” information to the terminal) before the abort sequence has reached the ELIC,
it would mistake a ‘0’ of the second frame as the start of a new frame. When the delayed
abort sequence arrives at the ELIC, the D-channel arbiter would then switch back to the
state “limited selection” and re-block the terminal. Thus the D-channel arbiter would
toggle between sending “available” and “blocked” information to the terminal, forever
aborting the terminal’s frame. The arbiter would have locked.
Semiconductor Group
0
PN
PN
PN
0
0
0
PN
PN
PN
line card
line card -
line card -
adapter -
phone
line card -
phone
phone
adapter -
phone
t
DCDU
Control Channel Delay
, the full selection counter value must be set so that the D-channel arbiter
Circuit Chain
ELIC + OCTAT-P
+ ISAC-P TE
ELIC + OCTAT-P
ELIC + OCTAT-P
+ ISAC-P TE +
ISAC-P TE +
ISAC-P TE
ELIC + QUAT-S +
ISAC-S TE
+ ISAC-P
TE +
SBCX +
ISAC-S
min.
4
9
9
4
Blocked → Available
2-39
Number of Frames (= 125 µs)
max.
8
13
13
8
Functional Block Description
min.
4
5
9
4
Available → Blocked
t
CCDD
PEB 20560
(e.g. after
max.
8
9
13
8
2003-08