DP83848YB_08 NSC [National Semiconductor], DP83848YB_08 Datasheet - Page 11

• Manufacturer Part Number: DP83848YB_08
• Manufacturer: NSC [National Semiconductor]

1.3 Clock Interface
1.4 LED Interface
See Table 3 for LED Mode Selection.
X1
X2
25MHz_OUT
LED_LINK
LED_SPEED
LED_ACT/COL
Signal Name
Signal Name
S, O, PU
S, O, PU
S, O, PU
Type
Type
O
O
I
Pin #
Pin #
34
33
25
28
27
26
CRYSTAL/OSCILLATOR INPUT: This pin is the primary clock
reference input for the DP83848YB and must be connected to a
25 MHz 0.005% (+50 ppm) clock source. The DP83848YB sup-
ports either an external crystal resonator connected across pins
X1 and X2, or an external CMOS-level oscillator source connect-
ed to pin X1 only.
RMII REFERENCE CLOCK: This pin is the primary clock refer-
ence input for the RMII mode and must be connected to a 50 MHz
0.005% (+50 ppm) CMOS-level oscillator source.
CRYSTAL OUTPUT: This pin is the primary clock reference out-
put 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.
25 MHz CLOCK OUTPUT:
In MII mode, this pin provides a 25 MHz clock output to the sys-
tem.
In RMII mode, this pin provides a 50 MHz clock output to the sys-
tem.
This allows other devices to use the reference clock from the
DP83848YB without requiring additional clock sources.
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 and Mode 3, 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.
SPEED LED: The LED is ON when device is in 100 Mb/s and OFF
when in 10 Mb/s. Functionality of this LED is independent of mode
selected.
ACTIVITY LED: In Mode 1, this pin is the Activity LED which is
ON when activity is present on either Transmit or Receive.
COLLISION/DUPLEX LED: In Mode 2, this pin by default indi-
cates Collision detection. For Mode 3, this LED output may be
programmed to indicate Full-duplex status instead of Collision.
11
Description
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