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DP83640 DEMO BOARD USER GUIDE
2.3
Device Register Access
2.3.1 Access MDIO Through MII
To access the device registers through the MII interface jumpers should be placed between pins
1 and 2 of J3 and J4. Figure 3 shows the default jumper settings for the MDIO/MDC access via
the MII interface.
Figure 3. Default MDIO/MDC Connection
2.3.2 Access MDIO Through USB
To access the device registers through the USB interface jumpers should be placed between pins
2 and 3 of J3 and J4.
2.3.3 Access MDIO Through Parallel Port
To access the device registers through the parallel port of the PC, the jumpers on J3 and J4 must
be removed. Figure 4 shows the connection between the parallel port and the device signals:
MDIO (J4, 2), MDC (J3, 2), and GND (J22, 1).
Figure 4. Direct Connect Cable with Line Resistors
