
RTL8305SB
2002/04/09
8
Rev.1.0
5.3 Port4 External MAC Interface Pins
The external device should be 2.5V compatible, because the digital output of the RTL8305SB is 2.5V. The input or
input/output pins listed below do not have internal pull-high resistors for connecting to external devices. External pull-high
resistors are recommended for those floating input pins without internal pull-high resistor if reduced power consumption is
desired.
In order to differentiate between MAC and PHY mode, the name of the pins change for PHY mode. For example:
RTL8305SB=MRXD[0]/PTXD[0], RTL8305S=MRXD[0]/MTXD[0].
Tip: Connect the input of Port4 to the output of the external device.
Pin Name
Pin No. Type
Description
MRXD[3:0]/
PTXD[3:0]
For PHY mode SNI, PTXD[0] is serial transmit data.
Because this pin can be connected to a 2.5V or 3.3V devices, these pins
have no internal pull-high resistor.
RTL8305SB = MRXD[3:0] / PTXD[3:0], RTL8305S = MRXD[3:0] /
MTXD[3:0]. In order to differentiate between MAC and PHY modes,
the RTL8305SB changes the pin name for PHY mode.
MRXDV/PTXEN
For PHY mode MII, this pin represents PTXEN, MII transmit enable.
For PHY mode SNI, this pin represents PTXEN, transmit enable.
Because this pin can be connected to a 2.5V or 3.3V device, this pin has
no internal pull-high resistor.
RTL8305SB = MRXDV/PTXEN, RTL8305S = MRXDV/MTXEN. In
order to differentiate between MAC and PHY mode, the RTL8305SB
changes the pin name for PHY mode.
MRXC/PTXC
For PHY mode MII/PHY mode SNI, it is transmit clock, PTXC (acts as output).
Because this pin can be connected to a 2.5V or 3.3V device, this pin has
no internal pull-high resistor.
RTL8305SB = MRXC/PTXC, RTL8305S = MRXC/MTXC. In order to
differentiate between MAC and PHY mode, the RTL8305SB changes
the pin name for PHY mode.
MCOL/PCOL
For PHY mode MII/PHY mode SNI, this pin represents PCOL collision
(acts as output)
Because this pin can be connected to a 2.5V or 3.3V device, this pin has
no internal pull-high resistor.
RTL8305SB = MCOL/PCOL, RTL8305S = MCOL. In order to
differentiate between MAC and PHY mode, the RTL8305SB changes the
pin name for PHY mode.
Cont…
Default
67,66,63,
61
I
For MAC mode MII, these pins are MRXD[3:0], MII receive data nibble.
For PHY mode MII, these pins are PTXD[3:0], MII transmit data nibble.
60
I
For MAC mode MII, this pin represents MRXDV, MII receive data valid.
59
I/O
For MAC mode MII, it is receive clock, MRXC (acts as input).
58
I/O
For MAC mode MII, this pin represents MCOL collision (acts as input)