
PRELIMINARY
XRT79L71
350
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
STEP 2 - Configure the Transmit Drive Monitoring block into the "Internal" Mode.
The user can accomplish this step by setting Bit 5 (Internal Transmit Drive Monitor) to "1" as depicted below.
NOTE: To implement "Transmit Output Drive Monitoring" via "Internal Means", then there is NO need to implement the
external connections via the MTIP and TTIP and MRING and TRING pins. In this case, the Transmit Drive Monitor
circuit will be monitoring (e.g., checking the TTIP/TRING signals for bipolar activity) by direction checking the pads
of the TTIP/TRING outputs themselves.
Once the user has implement this (above-mentioned) step, then the Transmit Drive Monitor block will proceed
to "internally" check the TTIP/TRING lines for bipolar activity. As long as the Transmit Drive Monitor block
detects a regular stream of bipolar pulses, then it will negate the "Transmit DMO Condition" by continuing to set
Bit 0 (Transmit DMO Condition), within the "LIU Alarm Status" Register, to "0" as depicted below.
NOTE: For most applications, the "Transmit DMO Condition" bit-field being set to "0" is a normal and a desirable condition.
FIGURE 161. A SCHEMATIC DESIGN, DEPICTING THE REQUIRED CONNECTIONS FOR "INTERNAL" TRANSMIT DRIVE
MONITORING
LIU Transmit Control Register (Address = 0x1304)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Internal
Transmit
Drive Monitor
Unused
TAOS
Unused
TxLEV
R/O
R/W
R/O
R/W
R/O
R/W
0
1
0
LIU Alarm Status Register (Address = 0x1303)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
Digital
LOS
Defect
Declared
Analog
LOS
Defect
Declared
FL
(FIFO Limit)
Alarm
Declared
Receive
LOL
Defect
Declared
Receive
LOS Defect
Declared
Receive
DS3/E3 LIU
Block
Transmit
DMO
Condition
R/O
0
R10
31.6
R12
100
J4
BNC
1
2
T4
T3001
1
6
3
4
R9 31.6
R11
100
U4
XRT79L71
T11
T10
P10
P11
TTIP
TRING
MTIP
MRING