
XRT7234
E3 UNI FOR ATM
x r
PRELIMINARY
REV. P1.0.0
74
Bit 0 - MARx (FERF and FEBE bit-field Loopback)
This “Read/Write” bit-field allows the user to specify whether the value of the FERF and FEBE bit-fields, in the “out-
bound” E3 frames; should be based upon “Receive E3 Framer” conditions or upon the content of the “Tx MA Byte”
register (Address = 2Ah).
FERF and FEBE values are based upon Receive E3 Framer Conditions
If the user selects “Receive E3 Framer” conditions, then the Transmit E3 Framer will set and clear the FERF and
FEBE bit-fields in response to the following conditions.
FERF Bit-field
– If the Receive E3 Framer (on the same UNI chip) is currently experiencing an LOS, AIS, or LOF condition,
then the Transmit E3 Framer will set the “FERF” bit-field (in the “outbound” E3 frame) to “1”. Conversely, if
the Receive E3 Framer is not experiencing any of these conditions, then the Transmit E3 Framer will set the
FERF bit-field (in the “outbound” E3 frame) to “0”.
FEBE Bit-field
– If the Receive E3 Framer detects a BIP-8 error in the “incoming” E3 frame, then the Transmit E3 Framer will
set the “FEBE” bit-field (in the “outbound” E3 frame) to “1”. Conversely, if the Receive E3 Framer does not
detect a BIP-8 error in the “incoming” E3 frame, then the Transmit E3 Framer will set the “FEBE” bit-field (in
the E3 “outbound” E3 frame) to “0”.
FEBE and FERF values are based upon the contents of the “Tx MA Byte” register
If the user selects the contents of the “Tx MA Byte” register, then whatever value has been written into bit 7 (FERF),
within the “Tx MA Byte” register (Address = 2Ah); will be the value of the “FERF” bit-field, in the “outbound” E3
frame. Likewise, whatever value has been written into Bit 6 (FEBE) within the “Tx MA Byte” register, will be the
value of the “FEBE” bit-field, in the “outbound” E3 frame.
Writing a “1” into Bit 0 (MAx) within the “Tx E3 Configuration” register configures the Transmit E3 Framer to set the
“FERF” and “FEBE” bit-fields (in the “outbound” E3 frames) to values based upon “Receive E3 Framer” conditions.
Writing a “0” into this bit-field configures the Transmit E3 Framer to set the “FEBE” and “FEBE” bit-fields (in the
“outbound” E3 frames) to the values written into bit-fields 6 and 7 within the “Tx MA Byte” register.
3.3.2.43 Tx GC Byte Register
This “Read/Write” byte-field allows the user to specify the contents of the GC byte-field in each outbound E3 frame.
Note: The contents of this register is ignored, if the LAPD Transmitter is enabled and has been configured to insert
the comprising octets of an “outbound” LAPD Message frame into the GC byte-field of each outbound E3 frame
Address = 29h, Tx GC Byte Register
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Transmit GC Byte
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0