![](http://datasheet.mmic.net.cn/260000/PSB2115F_datasheet_15948207/PSB2115F_94.png)
PSB 2115
PSF 2115
Functional Description
Semiconductor Group
94
11.97
2.5.8
In addition to the standard functions supporting the ISDN basic access, the IPAC
contains optional functions, useful in various terminal configurations.
The terminal specific functions
are enabled by setting bit TSF (STCR register) to “1”. This
has two effects:
In TE mode the MODE1/EAW line is defined as External Awake input, but additionally
this function is only enabled by setting STCR:TSF=1
Second, the interrupts SAW and WOV (EXIRD register) are enabled:
– SAW (Subscriber Awake) generated by a falling edge on the EAW line
– WOV (Watchdog Timer Overflow) generated by the watchdog timer. This occurs
when the processor fails to write two consecutive bit patterns in ADF1:
Terminal Specific Functions (TE mode only)
Watchdog Timer Control 1,0.
The WTC1 and WTC2 bits have to be successively written in the following manner within
128 ms:
As a result the watchdog timer is reset and restarted. Otherwise a WOV is generated.
Deactivating the terminal specific functions is only possible with a hardware reset.
Having enabled the terminal specific functions via TSF = 1, the user can make the IPAC
generate a reset signal by programming the Reset Source Select
RSS
bit (CIX0
register), as follows:
0
→
A reset signal is generated as a result of
– a falling edge on the EAW line (subscriber awake)
– a C/I code change (exchange awake).
– layer-1 part leaves power down state and supplies DCL and FSC clocks.
A falling edge on the EAW line also forces the DU line of the
IOM interface to zero.
Note:In case the layer-1 part of the IPAC is switched off (CONF:TEM=1), a falling
edge on EAW should normally induce the attached layer-1 device to leave
the power down state and supply clocking to IPAC via DCL and FSC.
A corresponding interrupt status (CIC or SAW) is also generated.
ADF1
WTC1
WTC2
WTC1
1
0
WTC2
0
1
1.
2.