
XRT7245
DS3 UNI FOR ATM
á
PRELIMINARY
REV. 1.03
62
bit of an ‘a(chǎn)ctivated’ interrupt, during the Interrupt
Service Routine. If the user selects this option, then
an interrupt will be automatically disabled following
its activation. The user must go back and write to the
appropriate register(s) in order to enable the interrupt
once again. This option is useful in preventing a re-
cursively occurring interrupt from “tying up the sys-
tem” and loading down the local μC/μP
Writing a ‘1’ to this bit-field configures the UNI to au-
tomatically disable interrupts, following their activa-
tion. Writing a ‘0’ to this bit-field configures the UNI to
leave the Interrupt Enable bits as is, following inter-
rupt activation.
Bit 4—AMI/B3ZS* (Line Code)
This “Read/Write” bit-field allows the user to specify
whether the DS3 line code should be in the AMI (Al-
ternate Mark Inversion) or B3ZS (Bipolar, with 3 Zero
Substitution) format.
Writing a “1” to this bit-field configures the line code
(of the Transmit and Receive DS3 Framers) to be
AMI. Writing a “0” to this bit-field, configures the line
code (of the Transmit and Receive DS3 Framers) to
be B3ZS. For more information into the AMI and
B3ZS format, please see Section 6.4.3.5.1.2.
Note:
This bit-field is ignored if Bit 3 is “1”.
Bit 3—Unipolar/Bipolar* (Line Code)
This “Read/Write” bit-field allows the user to config-
ure the Transmit and Receive DS3 Framers to trans-
mit/receive data in a Unipolar (Single-Rail) or Bipolar
(Dual Rail) format.
If the user selects the “Bipolar” format, then he/she
can manipulate Bit 4 (of this register) in order to select
the AMI or B3ZS line code.
Writing a “0” to this bit-field configures the Transmit
DS3 Framer to transmit data in a bipolar (dual-rail)
format; and the Receive DS3 Framer to receive data
from the “l(fā)ine” in a bipolar (dual-rail) format. Writing a
“1” to this bit-field configures the Transmit DS3 Framer
to transmit data in a unipolar (single-rail) format, and
the Receive DS3 Framer to receive data in a unipolar
format.
For more information on Unipolar and Bipolar formats,
please see Sections 6.4.3.5.1.1 and 6.4.3.5.1.2.
Bit 2—TxLineClk Inv
This “Read/Write” bit-field allows the user to config-
ure the Transmit DS3 Framer to update the outbound
DS3 data on the TxPOS and TxNEG output pins, on
either the rising or falling edge of TxLineClk.
Writing a “0” to this bit-field configures the Transmit
DS3 Framer to update TxPOS and TxNEG on the ris-
ing edge of TxLineClk.
Writing a “1” to this bit-field configures the Transmit
DS3 Framer to update TxPOS and TxNEG on the
falling edge of TxLineClk.
For more information on this feature, please see
Section 6.4.2.3.3.
Bit 1—RxLineClk Inv
This “Read/Write” bit-field allows the user to config-
ure the Receive DS3 Framer to “sample” the incom-
ing DS3 data at the RxPOS and RxNEG input pins,
on either the rising or falling edge of RxLineClk.
Writing a “0” configures the Receive DS3 Framer to
sample the RxPOS and RxNEG input pins on the
rising edge of the RxLineClk.
Writing a “1” configures the Receive DS3 Framer to
sample the RxPOS and RxNEG input pins on the fall-
ing edge of the RxLineClk.
For more information on this feature, please see
Section 7.1.2.1.2.4.
Bit 0—Reframe (Receive DS3 Framer)
When a “0” to “1” transition is detected in this bit-field,
then the Receive DS3 Framer will be forced to start a
frame search.
3.3.2.3
Part Number Register
Address = 02h, Part Number Register
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Part Number
RO
RO
RO
RO
RO
RO
RO
RO
0
0
0
0
0
0
0
1