
XRT7250
DS3/E3 FRAMER IC
á
REV. 1.1.1
88
ister. The purpose of this interrupt is to let the local
P know that the LAPD Transmitter has completed its
transmission of the LAPD Message frame (containing
the latest PMDL message) and is now ready to trans-
mit another LAPD Message frame.
A "0" in this bit-field indicates that the LAPD Message
frame Transmission Complete interrupt has not oc-
curred since the read of this register. A "1" in this bit-
field indicates that this interrupt has occurred since
the last read of this register.
NOTE: For more information on the TxLAPD Interrupt,
please see Section 3.2.6.
2.3.5.6
Transmit DS3 M-Bit Mask Register
(DS3 Applications)
Bit 7 - 5: TxFEBEDat[2:0]
These three (3) read/write bit-fields, along with Bit 4
of this register, allows the user to configure and trans-
mit his/her choice for the three (3) FEBE (Far-End
Block Error) bits in each outgoing DS3 Frame. The
user will write his/her value for the FEBE bits into
these bit-fields. The Transmit DS3 Framer block will
insert these values into the FEBE bit-fields of each
outgoing DS3 Frame, once the user has written a "1"
to Bit 4 (FEBE Register Enable).
NOTE: For more information on this feature, please see
Section 3.2.4.2.1.9.
Bit 4 - FEBE Register Enable
This Read/Write bit-field permits the user to configure
the Transmit DS3 Framer to insert the contents of
TxFEBEDat[2:0] into the FEBE bit-fields each out-
bound DS3 Frame.
Writing a "0" to this bit-field disables this feature (e.g.,
the Transmit DS3 Framer block will transmit the inter-
nally generated FEBE bits). Writing a "1" to this bit-
field enables this features (e.g., the internally gener-
ated FEBE bits are overwritten by the contents of the
TxFEBEDat[2:0] bit-field).
NOTE: For more information on this feature, please see
Section 3.2.4.2.1.9.
Bit 3 - Transmit Erred P-Bit
This Read/Write bit-field permits the user to insert er-
rors into the P-bits of the outgoing DS3 frames (via
the Transmit DS3 Framer). If the user enables this
feature, then the Transmit DS3 Framer block will pro-
ceed to invert each and every P-bit, from its comput-
ed value, prior to transmission to the Remote Termi-
nal.
Writing a "0" to this bit-field (the default condition) dis-
ables this feature (e.g., the correct P-bits are sent).
Writing a "1" to this bit-field enables this feature (e.g.,
the incorrect P-bits are sent).
NOTE: For more information on this feature, please see
Section 3.2.4.2.2.
Bit 2 - 0 M-Bit Mask[2:0]
These Read/Write bit-fields permit the user to insert
errors in the M-bits for Test and Diagnostic purposes.
The Transmit DS3 Framer automatically performs an
XOR operation on the actual contents of the M-bit
fields to these register bit-fields. Therefore, for every
'1' that exists in these bit-fields, will result in a change
of state of the corresponding M-bit, prior to being
transmitted to the Remote Terminal Equipment.
If the Transmit DS3 Framer is to be operated in the
normal mode (e.g., when no errors are being injected
into the M-bit fields of the outbound DS3 Frame), then
these bit-fields must be all “0’s”.
2.3.5.7
Transmit DS3 F-Bit Mask Register - 1
(DS3 Applications)
TXDS3 M-BIT MASK REGISTER (ADDRESS = 0X35)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
TxFEBEDat[2:0]
FEBE Reg
Enable
Tx Error
P-Bit
MBit Mask[2]
MBit Mask[1]
MBit Mask[0]
R/W
00
000