
QuadFALCTM
PEF 22554 E
T1/J1 Registers
Data Sheet
584
Rev. 1.2, 2006-01-26
Framer Receive Status Register 0
FRS0_T
Offset
Reset Value
Framer Receive Status Register 0
xx4CH
xxH
Field
Bits
Type
Description
LOS
7
r
Loss-of-Signal (Red Alarm)
Detection:
This bit is set when the incoming signal has “no transitions“ (analog
interface) or logical zeros (digital interface) in a time interval of T
consecutive pulses, where T is programmable by PCD register: Total
account of consecutive pulses: 16 < T < 4096.
Analog interface: The receive signal level where “no transition” is
declared is defined by the programmed value of LIM1.RIL(2:0).
Recovery:
Analog interface: The bit is reset in short-haul mode when the
incoming signal has transitions with signal levels greater than the
programmed receive input level (LIM1.RIL(2:0)) for at least M pulse
periods defined by register PCR in the PCD time interval. In long-haul
mode additionally bit RES.6 must be set for at least 250
s.
Digital interface: The bit is reset when the incoming data stream
contains at least M ones defined by register PCR in the PCD time
interval.
With the rising edge of this bit an interrupt status bit (ISR2.LOS) is set.
For additionally recovery conditions refer also to register LIM2.LOS1. The
bit is set during alarm simulation and reset if FRS2.ESC = 0D, 3D, 4D,
6D,7D and no alarm condition exists.
AIS
6
r
Alarm Indication Signal (Blue Alarm)
This bit is set when the conditions defined by bit FMR4.AIS3 are detected.
The flag stays active for at least one multiframe. With the rising edge of
this bit an interrupt status bit (ISR2.AIS) is set. It is reset with the
beginning of the next following multiframe if no alarm condition is
detected.The bit is set during alarm simulation and reset if FRS2.ESC =
0D, 3D, 4D, 7D and no alarm condition exists.
LFA
5
r
Loss of Frame Alignment
The flag is set if pulseframe synchronization has been lost. The
conditions are specified by bit FMR4.SSC(1:0). Setting this bit causes an
interrupt (ISR2.LFA). The flag is cleared when synchronization has been
regained. Additionally interrupt status ISR2.FAR is set with clearing this
bit.