Datasheet

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DP83849C
1.0 Pin Descriptions
The DP83849C pins are classified into the following inter-
face categories (each interface is described in the sections
that follow):
— Serial Management Interface
— MAC Data Interface
— Clock Interface
— LED Interface
— Reset and Power Down
— Strap Options
— 10/100 Mb/s PMD Interface
— Special Connect Pins
— Power and Ground pins
Note: Strapping pin option. Please see Section 1.6 for strap
definitions.
All DP83849C signal pins are I/O cells regardless of the
particular use. The definitions below define the functionality
of the I/O cells for each pin.
1.1 Serial Management Interface
1.2 MAC Data Interface
Type: I Input
Type: O Output
Type: I/O Input/Output
Type OD Open Drain
Type: PD,PU Internal Pulldown/Pullup
Type: S Strapping Pin (All strap pins have weak in-
ternal pull-ups or pull-downs. If the default
strap value is to be changed then an exter
-
nal 2.2 kΩ resistor should be used. Please
see Section 1.6 for details.)
Signal Name Type Pin # Description
MDC I 67 MANAGEMENT DATA CLOCK: Synchronous clock to the MDIO
management data input/output serial interface which may be asyn
-
chronous to transmit and receive clocks. The maximum clock rate is
25 MHz with no minimum clock rate.
MDIO I/O 66 MANAGEMENT DATA I/O: Bi-directional management instruc-
tion/data signal that may be sourced by the station management entity
or the PHY. This pin requires a 1.5 kΩ pullup resistor.
Signal Name Type Pin # Description
TX_CLK_A
TX_CLK_B
O 12
50
MII TRANSMIT CLOCK: 25 MHz Transmit clock output in 100 Mb/s
mode or 2.5 MHz in 10 Mb/s mode derived from the 25 MHz reference
clock.
Unused in RMII mode. The device uses the X1 reference clock input
as the 50 MHz reference for both transmit and receive.
SNI TRANSMIT CLOCK: 10 MHz Transmit clock output in 10 Mb SNI
mode. The MAC should source TX_EN and TXD_0 using this clock.
TX_EN_A
TX_EN_B
I 13
49
MII TRANSMIT ENABLE: Active high input indicates the presence of
valid data inputs on TXD[3:0].
RMII TRANSMIT ENABLE: Active high input indicates the presence
of valid data on TXD[1:0].
SNI TRANSMIT ENABLE: Active high input indicates the presence of
valid data on TXD_0.
TXD[3:0]_A
TXD[3:0]_B
I 17,16,15,14
45,46,47,48
MII TRANSMIT DATA: Transmit data MII input pins, TXD[3:0], that
accept data synchronous to the TX_CLK (2.5 MHz in 10 Mb/s mode
or 25 MHz in 100 Mb/s mode).
RMII TRANSMIT DATA: Transmit data RMII input pins, TXD[1:0],
that accept data synchronous to the 50 MHz reference clock.
SNI TRANSMIT DATA: Transmit data SNI input pin, TXD_0, that ac-
cept data synchronous to the TX_CLK (10 MHz in 10 Mb/s SNI mode).