PEB2080 SIEMENS [Siemens Semiconductor Group], PEB2080 Datasheet - Page 37

• Manufacturer Part Number: PEB2080
• Description: S/T Bus Interface Circuit(SBC)
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

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3.1
The internal finite state machine of the SBC controls the activation/deactivation procedures,
switching of test loops and transmission of special pulse patterns. Such actions can be initiated by
signals on the S transmission line (INFO’s) or by control (C/l) codes sent over the IOM interface.
The exchange of control information in the C/l channel is state oriented. This means that a code in
the C/l channel is repeated in every IOM frame until a change is necessary. A new code must be
found in two consecutive IOM frames to be considered valid (double last look criterion).
3.2
In LT-T and LT-S applications the IOM interface should be kept active, i.e. the clocks DCL and FSC
are always present. In this case commands in the C/l channel may also be handed over to the SBC
in the “power down” state (state F3 for LT-T/state G1 for LT-S: see figures 24 and 25).
In TE and NT applications the IOM interface can be switched off in the inactive state, reducing
power consumption to a minimum (on the order of 5 mW and 6.5 mW for PEB and PEF,
respectively). In this deactivated state the clock lines are low and the data lines are high.
For the TE case the procedure is shown in figure 20. After detecting the code DIU (Deactivate
Indication Upstream, i.e. from TE to NT/LT-S) from the downstream unit, the SBC responds by
transmitting DID (Deactivate Indication Downstream) during subsequent frames and stops the
timing signals synchronously with the end of the last C/l channel bit of the fourth frame.
Figure 20
Deactivation of the IOM
Semiconductor Group
Operational Description
General
Clocking, Reset and Initialization
®
Interface
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Operational Description