STLC5412FN STMICROELECTRONICS [STMicroelectronics], STLC5412FN Datasheet - Page 36

• Manufacturer Part Number: STLC5412FN
• Description: 2B1Q U INTERFACE DEVICE ENHANCED WITH DECT MODE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STLC5412
register is required to power up the UID.
GCI: when GCI ”NT master of the clocks”configura-
tion is selected, UID provides the GCI clocks
needed for control channel transfer; PUP control in-
struction is provided to the UID by pulling low the
Bx data input; STLC5412 then reacts sending GCI
clocks. It is possible to operate an automatic power
up of the UID when a wake up tone is detected
from the line by connecting the LSD output directly
to the Bx input.
GCI: when NT1-2 or LT configuration is selected
(M0 = 0), the UID is powered up after configura-
tion setting by the PUP code (0000) on C/I Chan-
nel.
Power down control
A control instruction PDN in ACT register is re-
quired to power down the device after a period of
activity. PDN forces directly the device to the low
power state without sequencing through any of
the de-activation states. It should therefore only
be used after the UID has been put in the line de-
activated state. PDN has no influence on the con-
tent of the internal registers, but immediately
stops the output clocks when UID is in master
mode and in W/DSI mode.
In GCI mode, UID send first two times code
DI(1111) on C/I channel before powering down at
the end of the assigned GCI channel.
The DI code purpose is similar to PDN code but
power down state is entered only when the line is
entirely deactivated (state H1 or J1). The DI com-
mand is recommended.
Power up state
Power up transition enables all analog and digital
circuitry, starts the crystal oscillator and internal
clocks. The LSD output is in the high impedance
state even if a tone is detected from the line. As
for PDN, PUP has no influence on the content of
the internal registers
Power down state
Following a period of activity in the power up
state, the power down state may be re-entered as
described above. Configuration Registers remain in
their current state. PDN and DI have no influence
on the content of the internal registers: it is then
possible, for instance, after a normal deactivation
procedure followed by a power down command, to
power up again the device in order to operate di-
rectly a Warm Start procedure.
ACTIVATION/DEACTIVATION SEQUENCING
Activation/deactivation signals onto the line are in
accordance with the activation/deactivation state
matrix given in Appendix A.
36/74
CASE OF RESTRICTED ACTIVATION
The standard specifies a mode where the U inter-
face can be turned on without the need to activate
the S/T interface provided this function is supported
at both ends of the loop. In this condition Mainte-
nance channel is available, typically for setting
loop-backs in the NT for error rate testing and other
diagnostics.
When this mode is enabled, bit M47 on the line in
LT to NT direction becomes the uoa bit. Setting
UAR activation command in the LT chip will set
uoa bit equal zero on the line. Detection of uoa bit
equal zero by the NT will inhibit activation of the
S/T interface. This results in SN3 signal in the NT
to LT direction, which causes generation of UAI
indication by the LT U device when superframe
synchronized.
If during restricted activation operation, a TE
starts to try activate the S/T interface by sending
info 1, the NT can pass this request to the LT via
M47 bit, the sai bit. This bit is set equal one by
writing AR command to the Activation Control
Register. sai bit received equal one causes gen-
eration of an AP indication by the LT U device.
RESET OF ACTIVATION/DEACTIVATION STATE
MACHINE
When the device is either powered-up or down, a
control instruction RES resets the activation con-
troller ready for a cold start. That feature can be
used if the far-end equipment fails to warm start,
for example if the line card or NT has been re-
placed or if in a regenerator, the loss of synchro-
nisation of the second section imply the reset of
the first section for a further cold start. The con-
figuration registers remain in their selected value.
HARDWARE RESET
When GCI configuration is selected, pin RES acts
as a logical hardware Reset. The device is en-
tirely reset including activation/deactivation state
machine and configuration registers. Configura-
tion pins bias excluding MW define the eventual
new configuration. Pin MW must be maintained at
the 0 Volt for GCI configuration setting.
It is possible to operate a similar ”complete reset”
of UID by setting high bit RST in the RXOH com-
mand register. In this last case the Control inter-
face remains enabled. Refer to User guide for
Software reset procedure.
QUIET MODE
It is possible to force the device in a quiet mode in
which UID does not react to any line wake-up
tone and LSD pin remains high. There are two