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PSB 2115
PSF 2115
Operational Description
Semiconductor Group
188
11.97
3.6
Control of Layer-1
3.6.1
In LT-T and LT-S applications
the IOM interface should be kept active, i.e. the clock
DCL and the frame sync FSC (inputs) should always be supplied by the system.
In TE applications
the IOM-2 interface can be switched off in the inactive state,
reducing power consumption to a minimum. In this deactivated state the clock line is low
and the data lines are high.
In TE mode
the IOM-2 interface can be kept active while the S interface is deactivated
by setting the CFS bit to "0" (CONF register). This is the case after a hardware reset. If
the IOM-2 interface should be switched off while the S interface is deactivated, the CFS
bit should be set to "1". In this case the internal oscillator is disabled when no signal (info
0) is present on the S bus
and the C/I command is ’1111’ = DIU (refer to
chapter 3.6.2
).
If the TE wants to activate the line, it has first to activate the IOM-2 interface either by
using the "Software Power Up" function (SPCR:SPU bit) or by setting the CFS bit to "0"
again.
For the TE case the deactivation procedure is shown in
figure 90
. After detecting the
code DIU (Deactivate Indication Upstream) the layer 1 of the IPAC responds by
transmitting DID (Deactivate Indication Downstream) during subsequent frames and
stops the timing signals synchronously with the end of the last C/I (C/I0) channel bit of
the fourth frame.
Activation/Deactivation of IOM
-2 Interface