AL103 Revision 1.0
This mode of PHY management is very useful for unmanaged switches. The operating mode of the
link can be changed by programming the mode pin of the PHY through a jumper.
The AL103 also supports 100Base-TX transceivers without a MDIO interface or MII to MII
interface. When MDIO is disabled, the AL103 will operate in the operation mode specified in the
port configuration register (register 0D to 1C).
3.13.4 Non Auto-negotiation Mode
The AL103 can also turn off the auto-negotiation capability of the PHY. When auto-negotiation is
turned off, the AL103 is in the slave mode and the transceiver will determine the link’s operating
mode.
3.13.5 Other PHY Options
Some Legacy Fast Ethernet devices and other low cost devices have no auto-negotiation capability.
In those cases when the transceiver will not be able to perform auto-negotiation, the switch
transceiver will typically do a parallel detection and update the information in the transceiver’s
register. Unfortunately, such register addresses are vendor specific. The AL103 provides a register
(register 05) to specify the register address of the PHY for the AL103 to read. The AL103 will read
from that register and configure the port operation accordingly.
Register 05 also provides some additional flexibility’s for some of the PHYs in the market. In
general, the system designer should set the ID of the PHY devices as 0 for port 0, 1 for port 1, and 7
for port 7. Certain PHYs utilize PHY address 00000 as a broadcast address. Bit 1 of the register 05
allows the AL103 to start with PHY address 01000. This provision allows the engineers to work
around the PHY’s that have problems handling address 00000.
Quad PHYs may have 2-port ordering in the chip pinout, both clockwise and counter clockwise.
Register 05 bit 2, programs the AL103 port order to go in either direction. This provision enables
engineers to easily implement designs with any PHY.
There is also a slow MDIO clock (17 KHz) available for PHY that is not capable of handling a high
speed MDIO clock.
If for some reason, the transceiver is connected to a device and that device fails to auto-negotiate,
the AL103 will default the data rate and duplex mode to the default setting in the port configuration
register.
3.14 EEPROM Interface
The AL103 provides three functions with the EEPROM interface: system initialization, obtaining
system status, and reconfiguring the system in real time. The AL103 uses the 24C02 serial
EEPROM device (2048 bits organized as 256 bits x 8).
3.14.1 System Initialization
The EEPROM interface is provided so that the manufacturer can provide a pre-configured system
to their customers which allows customers to change or reconfigure their system and retain their
preferences. The EEPROM contains configuration and initialization information, which will be
accessed at power up or reset.
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Reference Only / Allayer Communications
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