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PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
61
3.3.2.2
UNI I/O Control Register
Bit 7—LOC (Loss of Clock)Enable
This “Read/Write” bit-field allows the user to enable
or disable the LOC (Loss of Clock) features, within
the UNI IC.
If the LOC feature is enabled, then an internal LOC
circuit will be active, and will continuously check for
transitions in both the TxInClk input pin and in the
RxLineClk input pins. If a “Loss of Clock” event oc-
curs, such that none of these signals are available to
the UNI device, then the LOC circuitry will force the
Rdy_Dtck to be asserted in order to prevent the cur-
rent read or write operation (over the Microprocessor
Interface) from “hanging up” for an indefinite period.
If the LOC feature is disabled, then there will be no
protection against “Loss of Clock” induced “hang-
ups” of a read or write cycle, over the Microprocessor
Interface.
Writing a “0” to this bit-field disables the LOC feature.
Conversely, writing “1” to this bit-field enables it.
For more information on this feature, please see
Section 3.4.
Bit 6—Test PMON
This “Read/Write” bit-field allows the user to perform
some testing with the Performance Monitor Regis-
ters. Writing a “1” to this bit-field converts the PMON
Register to be of the “Read/Write” type. Writing a “0”
to this bit-field, causes the PMON Registers to be of
the “Reset upon Read” type.
Bit 5—Int En Reset (Automatic Reset of Interrupt
Enable Bits) Select
This “Read/Write” bit-field allows the user to configure
the UNI to automatically clear the “Interrupt Enable”
T
IM
R
EF
S
EL
[1, 0]
T
RANSMIT
DS3 F
RAMER
T
IMING
R
EFERENCE
T
RANSMIT
PLCP P
ROCESSOR
T
IMING
R
EFERENCE
T
RANSMIT
PLCP P
ROCESSOR
—
S
TUFF
C
ONTROL
A
LGORITHM
00
RxLineClk—Receive DS3
Framer
(For more information please
see Section 6.4.3.4.1)
Receive PLCP Processor
(For more information please
see Section 6.3.3.1)
Stuff Control is computed from
Transmit PLCP Timing Reference
(e.g., the Receive PLCP Processor)
(For more information please see
Section 6.3.3.1)
01
Framing is asynchronous from
Power On. Timing is derived
from the TxInClk pin
(For more information please
see Section 6.4.3.4.2)
Framing is derived from the 8
kHZ reference signal at the
8KRef input pin.
(For more information please
see Section 6.3.3.1)
Stuff Control is computed from
Transmit PLCP Timing Reference
(e.g., the 8KRef input pin.)
(For more information please see
Section 6.3.3.1)
10
Framing is derived from the
TxFrameRef input pin.
(For more information, please
see Section 6.4.3.4.3)
Framing/Timing is asynchro-
nous
(For more information, please
see Section 6.3.3.1)
Stuff Control is based on the state
of the “StuffCtl” input pin.
(For more information, please see
Section 6.3.3.1)
11
Framing is asynchronous from
Power On. Timing is derived
from the TxInClk pin
(For more information please
see Section 6.4.3.4.2)
Framing/Timing is asynchro-
nous
(For more information please
see Section 6.3.3.1)
Stuff Control is based upon a pre-
defined fixed stuffing pattern
(For more information please see
Section 6.3.3.1)
Address = 01h, UNI I/O Control 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
LOC Enable
Test PMON
Interrupt
Enable Reset
AMI/B3ZS*
Unipolar/
Bipolar*
TxLine Clk
Inv
RxLine Clk
Inv
Reframe
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
1
0
1
0
0
0
0
0