xr
PRELIMINARY
XRT86VL38
REV. P1.0.6
OCTAL T1/E1/J1 FRAMER/LIU COMBO
36
RxTSEL
D5
C6
I
Receive Termination Control
Upon power up, the receivers are in "High" impedance. Switching to
internal termination can be selected through the microprocessor inter-
face by programming the appropriate channel register. However, to
switch control to the hardware pin, RxTCNTL must be programmed to
"1" in the appropriate global register. Once control has been granted
to the hardware pin, it must be pulled "High" to switch to internal ter-
mination.
N
OTE
: Internally pulled "Low" with a 50k
Ω
resistor.
TRANSMIT LINE INTERFACE
S
IGNAL
N
AME
420 P
KG
B
ALL
#
P
IN
#
T
YPE
D
ESCRIPTION
TTIP0
TTIP1
TTIP2
TTIP3
TTIP4
TTIP5
TTIP6
TTIP7
F3
G3
J3
K3
M3
P3
T3
U3
F3
H4
J3
K1
M5
N2
R4
T1
O
Transmit Positive Analog Output
TTIP is the positive differential output to the line interface. This out-
put pin, along with the corresponding TRING output pin, function as
the Transmit DS1/E1 output signal drivers for the XRT86VL38
device.
The user is expected to connect this signal and the corresponding
TRING output signal to a 1:2 step up transformer for proper opera-
tion.
Whenever the Transmit Section of the XRT86VL38 device generates
and transmits a “positive-polarity” pulse onto the line, this output pin
will be pulsed to a “higher-voltage” than its corresponding TRING
output pins.
Conversely, whenever the Transmit Section of the XRT79L71 device
generates and transmit a “negative-polarity” pulse onto the line, this
output pin will be pulsed to a “lower-voltage” than that of the TRING
output pins.
This output pin will be tri-stated whenever the user sets the “TxON”
input pin or register bit (0xnF02, bit 3) to “0”.
N
OTE
: This pin should have a series line capacitor of 0.68
µ
F for DC
blocking purposes.
RECEIVE LINE INTERFACE
S
IGNAL
N
AME
420 P
KG
B
ALL
#
484 P
KG
B
ALL
#
T
YPE
D
ESCRIPTION
RxTSEL (pin)
Rx Termination
External
Internal
0
1
Note: RxTCNTL (bit) must be set to "1"