
LXT9785 and LXT9785E Advanced 8-Port 10/100 Mbps PHY Transceivers
90
Datasheet
Document Number: 249241
Revision Number: 007
Revision Date: August 28, 2003
Table 32. Intel
LXT9785/LXT9785E Miscellaneous Signal Descriptions – BGA23 (Sheet 1 of 4)
Ball/Pin
Designation
Symbol
Type
1
Signal Description
2
BGA23
PQFP
N3,
M4
94
93
TxSLEW_0
TxSLEW_1
I, ST, ID
Tx Output Slew Controls 0 and 1
Defaults.
These pins are read at startup or reset. Their value at
that time is used to set the default state of Register bits
27.11:10 for all ports. These register bits can be read
and overwritten after startup / reset.
These pins select the TX output slew rate for all ports
(rise and fall time) as follows:
TxSLEW_1
TxSLEW_0
Slew Rate (Rise and Fall
Time)
0
0
3.3 ns
0
1
3.6 ns
1
0
3.9 ns
1
1
4.2 ns
D5
50
PAUSE
ID, I, ST
Pause Default.
This pin is read at startup or reset. Its value at that time
is used to set the default state of Register bit 4.10 for
all ports. This register bit can be read and overwritten
after startup / reset.
When High, the LXT9785/9785E advertises Pause
capabilities on all ports during auto-negotiation.
This pin is shared with RMII-RxER1. An external pull-
up resistor (see applications section for value) can be
used to set Pause active while RxER1 is three-stated
during H/W reset. If no pull-up is used, the default
Pause state is set inactive via the internal pull-down
resistor.
L14
174
PWRDWN
I, ST, ID
Power-Down.
When High, forces the LXT9785/9785E into global
power-down mode.
Pin is not on JTAG chain.
M15
175
RESET
I, ST, IP
Reset.
This active low input is ORed with the control register
Reset Register bit 0.15. When held Low, all outputs are
forced to inactive state.
Pin is not on JTAG chain.
1. Type Column Coding: I = Input, O = Output, OD = Open Drain Output, ST = Schmitt Triggered Input, TS =
Three-State-able Output, SL = Slew-rate Limited Output, IP = Weak Internal Pull-Up, ID = Weak Internal
Pull-Down.
2. The IP/ID resistors are disabled during hardware power-down mode.