AN2333 Freescale Semiconductor / Motorola, AN2333 Datasheet - Page 2

• Manufacturer Part Number: AN2333
• Description: Maximizing the Performance of Two Fast Ethernet Links on MSC8101 FCCs
• Manufacturer: Freescale Semiconductor / Motorola

IEEE 802.3 Ethernet Basics
1.1 Ethernet Transceiver
2
1
For details, see the Intel® data sheet for the LXT970/970A Fast Ethernet transceiver, which is available at
http://www.intel.com under Networking and Communications Design Components.
In most systems, the Ethernet medium is accessed from the controller through an Ethernet transceiver.
This section discusses how the Ethernet transceiver on the MSC8101ADS is configured and also
describes the bus interface between this transceiver and the MSC8101.
The MSC8101ADS uses the LXT970 Ethernet transceiver to access a 10/100 Base-T Ethernet port that
ends with a standard RJ-45 Ethernet jack. The main features of this Ethernet transceiver are as follows:
• IEEE 802.3 compliant.
• 10 Base-T and 100 Base-TX using a single RJ-45 connection.
• Support for auto negotiation
• Media-independent interface (MII) with extended register capability.
• 100Base-FX fiber optic capable.
• Standard CSMA/CD or full-duplex operation.
• Configurable via MII serial port or external control pins.
• Configurable for DTE or switch applications.
• Integrated LED drivers.
The Ethernet transceiver hardware configuration pins determine the default behavior of the transceiver
when it is connected to a line. These pins also provide the transceiver with a 5-bit MII address. The
MSC8101 device interconnects through two pins,
to access the device registers for configuration. Several Ethernet transceivers can share the
MDIO
from the same manufacturers have in common the base subset of registers, facilitating their control
software design.
Register 0: Control
Register
Register 1: Status Register
Register 4:
Auto-Negotiation
Advertisement Register
Register 20: Chip Status
Register
serial interface signals as long as they have different MII addresses. Also, Ethernet transceivers
Freescale Semiconductor, Inc.
Register
For More Information On This Product,
1
Table 1 shows the transceiver registers and bits that must be configured.
Table 1. Main Transceiver Registers
Go to: www.freescale.com
0.15 Reset chip
0.14 Enable Loopback
0.13 Set Link Speed Selection
0.12 Auto-Negotiation Mode Enable
0.09 Restart Auto-Negotiation Process
0.08 Set Link Duplex Mode
1.2 Get Link Status (Up/Down)
4.8 100BASE-TX full-duplex capable
4.7 100BASE-TX half-duplex capable
4.6 10BASE-T full-duplex capable
4.5 10BASE-T half-duplex capable
4.4:0 Selector Field - <00001> = IEEE 802.3
20.12 Get Duplex Mode
0.11 Get Speed
Bits
MDC
and
MDIO
, that provide a bidirectional serial bus
MDC
and