Specifications

DP83848Q-Q1

SNLS341C –MARCH 2011–REVISED MARCH 2015

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3.5 Clock Interface

SIGNAL TYPE PIN NO. DESCRIPTION

NAME

X1 I 28 CRYSTAL/OSCILLATOR INPUT: This pin is the primary clock reference input for the

DP83848Q-Q1 and must be connected to a 25 MHz 0.005% (±50 ppm) clock source. The

DP83848Q-Q1 supports either an external crystal resonator connected across pins X1 and

X2, or an external CMOS-level oscillator source connected to pin X1 only.

RMII REFERENCE CLOCK: This pin is the primary clock reference input for the RMII mode

and must be connected to a 50 MHz 0.005% (±50 ppm) CMOS-level oscillator source.

X2 O 27 CRYSTAL OUTPUT: This pin is the primary clock reference output to connect to an external

25 MHz crystal resonator device. This pin must be left unconnected if an external CMOS

oscillator clock source is used.

CLK_OUT O 21 MII 25 MHz CLOCK OUTPUT: This pin provides a 25 MHz clock output to the system. This

allows other devices to use the reference clock without requiring additional clock sources.

RMII 50 MHz CLOCK OUTPUT: Tthis pin provides a 50 MHz clock output to the system. For

RMII mode, it is not recommended that the system clock out be used as the reference clock to

the MAC. See SNLA076 for more details.

3.6 LED Interface

See Table 5-2 for LED Mode Selection.

SIGNAL NAME TYPE PIN NO. DESCRIPTION

LED_LINK S, O, PU 22 LINK LED: In Mode 1, this pin indicates the status of the LINK. The LED will be

ON when Link is good.

LINK/ACT LED: In Mode 2, this pin indicates transmit and receive activity in

addition to the status of the Link. The LED will be ON when Link is good. It will

blink when the transmitter or receiver is active.

3.7 RESET

SIGNAL NAME TYPE PIN NO. DESCRIPTION

RESET_N I, PU 23 RESET: Active Low input that initializes or re-initializes the DP83848Q-Q1 .

Asserting this pin low for at least 1 µs will force a reset process to occur. All internal

registers will re-initialize to their default states as specified for each bit in the

Section 5.6. All strap options are re-initialized as well.

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