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Data Sheet
125
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description E1/T1/J1
3.7.6
Transmit Line Monitor
The transmit line monitor (see principle in Figure 38) compares the transmit line current on XL1 and XL2 with an
on-chip transmit line current limiter. The monitor detects faults on the primary side of the transformer indicated by
a highly increased transmit line current (more than 120 mA for at least 3 consecutive pulses sourced by VDDX)
and protects the device from damage by setting the transmit line driver XL1/2 into high-impedance state
automatically (if enabled by XPM2.DAXLT = 0, see XPM2_E). The current limiter checks the actual current value
of XL1/2 and if the transmit line current drops below the detection limit the high-impedance state is cleared.
Two conditions are detected by the monitor:
Transmit line ones density (more than 31 consecutive zeros) indicated by FRS1.XLO (FRS1_E).
Transmit line high current indicated by FRS1.XLS.
In both cases a transmit line monitor status change interrupt is provided.
Shorts between XL1 or XL2 and V
DD , VDDC or VDDP are not detected.
Note that shorts between XL1 and XL2 cannot be detected. This way a short between XL1 and XL2 will not harm
the device.
Figure 38
Transmit Line Monitor Configuration
3.8
Multi Function Ports
Several signals are available on the multi function ports, see Table 31 and PC1_E. After reset, input function is
selected (SYPR or SYPX) .
Four multi function ports (MFP) for RX - so called as RPA, RPB, RPC, RPD - and four MFPs for TX - so called as
XPA, XPB, XPC, XPD - are implemented for each channel.
The functions of RPA, RPB, RPC and RPD are configured by PC1.RPC1(3:0), PC2.RPC2(3:0), PC3.RPC3(3:0)
7.5
75
Non generic 60
58
000000
00
--
Reset values
56
000000
00
2
DCIM
Mode
Generic
20
20202020202020-20 -20 -20 -20 -20 -20 -20 -20
7.5
DCIM
mode
Non generic 28
28
-28 -28 -28 -28 -28 -28 -28 -28
1) The values in this row refers to an ideal application without any parasitics. Any other parasitic resistances have to be taken
into account when calculating the final value of the output serial resistors.
Table 30
Recommended Pulse Shaper Programming for E1 with registers TXP(16:1) (cont’d)
R
SER
Z
0
Transmit
Line
Interface
Mode
TXP values, decimal
ITS10936
Pulse
Shaper
Monitor
Line
TRI
XDATA
XL1
XL2