PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 142

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Semiconductor Group
4.3.13
Note 39: See "Basic Operating Mode", page 50, for setting this mode.
If the LT transceiver is available and ready for activation, e.g. if the LT is not in the reset
or in any test state, the NT IEC-Q will start in this mode one single activation attempt after
leaving the "TEST" state, i.e. after being reset. In this case activation proceeds as
described in the previous sections.
However, If the LT is not ready for activation, the NT will periodically start a new
activation attempt every 15 seconds, till the LT side will be available and ready for
activations initiated by the NT side. See "State Transition Diagram in NT-Auto Activation
Mode", page 162.
4.3.14
Note 40: This function is only available if the NT mode in conjunction with the
In some NT and TE applications in the µP mode, the IOM
needed (e.g. inband signaling, some PC card applications etc.). In such cases it is
possible to control the internal state of the pin DIN via the MSB of the CIWU register (see
"CIWU-Register", page 217). Setting the SPU (software power up) bit to "0" in the NT
mode will cause the DIN signal to be set internally to "0", regardless of the value of the
pin DIN. Setting the SPU bit to "1", which is the default value after reset, will set the pin
DIN transparent to the internal circuit, see Figure 69 below.
Figure 69
Example for Activation with µP
Assumption: The C/I-Channel is being controlled via µP (i.e., SWST:CI=1, see "C/I
Channel Access", page 100).
DIN
microprocessor mode (PMODE = "1") are used. Note also that if the
IOM
page 53) activation in µP NT mode without IOM
Activation Attempt Initiated by NT in NT-Auto Activation Mode
Activation in the µP-NT Mode
IEC-Q
DIN Control via CIWU:SPU in NT µP Mode
interface
®
-2 clock disable mode is set (see "IOM
µP
CIWU:SPU= 1
default
Transceiver
Core
142
DIN
GND
®
IEC-Q
-2 interface is functionally not
®
interface
-2 Enable/Disable Mode",
®
Operational Description
µP
-2 will not be possible.
CIWU:SPU= 0
Transceiver
Data Sheet 01.99
Core
PEB 2091
PEF 2091