PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 164

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

Semiconductor Group
RES
SSP
TIM
Pins
Pin-Res
Pin-SSP
Pin-DT
Note 44: If one of the pin configurations Pin-Reset, Pin-SSP or Pin-DT is being
Microprocessor
SPU=0
used, C/I command (especially RES, SSP or DT) will not be executed, i.e.
pin setting has higher priority than C/I Channel setting.
Reset
Unconditional command which resets the transceiver core (see "Reset
Behavior", page 94). Especially the EC- and EQ-coefficients are set to zero.
Send Single Pulses
Unconditional command which requests the transmission of single pulses
on the U-interface. The pulses are issued at 1.5 ms intervals and have a
duration of 12.5 s.
The chip is in the "Test" state, the Receiver will not be reset.
Timing
In the NT mode the IEC-Q is requested to continue providing timing signals
and not to leave the "Power-up" state.
Pin-Reset
Corresponds to a low level at pin RES. Resets the transceiver core and all
registers except for register STCR in the microprocessor mode (see "Reset
Behavior", page 94). C/I-message DEAC will be issued. The duration of the
reset pulse must be 30 ns minimum.
Pin-Send Single Pulses
Applies only in stand-alone mode. Corresponds to a high-level at pin TSP in
stand-alone mode. The function of this pin is the same as of the C/I-code
SSP. C/I-message DR will be issued. The high-level must be applied
continuously for single pulses.
Pin-Data Through
Applies only in stand-alone mode. This function is activated when both pins
RES and TSP are active (RES = ’0’ and TSP = ’1’). The function of this pin
is the same as of the C/I-code DT.
This condition applies only in the microprocessor mode. Setting the
CIWU: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.
See "Activation in the µP-NT Mode", page 142.
164
Operational Description
Data Sheet 01.99
PEB 2091
PEF 2091