LAN83C183 Datasheet, PDF (74/113 Pages) SMSC Corporation – FAST ETHERNET PHYSICAL LAYER DEVICE

4.1 SIGNAL DESCRIPTION
The MI serial port has eight pins:
• MDC: serial shift clock input pin
• MDIO: bidirectional data pin
• MDINTn: interrupt pin
• MDA[4:0]n: physical address pins
The MDA[4:0]n pins configure the device for a particular address, from 0b0000 to
0b1111, such that 16 devices can exist in the same address domain, and each be
addressed separately over the MI serial port. When an MI read or write cycle occurs,
the device compares the internally inverted and latched state of the MDA[4:0]n pins
to the PHYAD[4:0] address bits of the MI frame. If the states compare, the device
knows it is being addressed.
The MDA[4:0]n inputs share the same pins as the MDINTn and PLED[3:0]n outputs,
respectively. At powerup or reset, the PLED[3:0]n and MDINTn output drivers are 3-
stated for an interval called the
power-on reset time. During the power-on reset interval, the value on these pins is
latched into the device, inverted, and used as the MI serial port physical device
addresses.
SMSC DS – LAN83C183
74
Rev. 12/14/2000