Specifications
Chapter 3 Hardware
44 Reference Manual ReadyBoard 800
10/100BaseT Ethernet Controller
Ethernet Port 1 uses an Intel 82551ER, 32-bit PCI controller that features enhanced scatter-gather bus
mastering capabilities, which enables the 82551ER to perform high-speed data transfers over the PCI
bus. The 82551ER bus master capabilities enable the component to process high-level commands and
perform multiple operations, thereby off-loading communication tasks from the system CPU.
• Backward software compatible to the 82559, 82558, and 82557
• Chained memory structure
• Full duplex or half-duplex support
• Full duplex support at 10 Mbps and 100 Mbps
• In half-duplex mode, performance is enhanced by a proprietary collision reduction mechanism.
• IEEE 802.3 10BaseT/100BaseT compatible physical layer to wire transformer
• Provides two LEDs for each port (speed, and link and activity are shared)
• Data transmission with minimum interframe spacing (IFS).
• IEEE 802.3u Auto-Negotiation support
• 3 kB transmit and 3 kB receive FIFOs (helps prevent data underflow and overflow)
• IEEE 802.3x 100BASE-TX flow control support
• Improved dynamic transmit chaining with multiple priorities transmit queues
• Supports a RJ-45 connector with magnetics integrated into the RJ-45 connector.
Tables 3-14 describes the pin-outs and signals of standard Ethernet port, Ethernet Port 1.
Table 3-14. Ethernet Port 1 Pin/Signal Descriptions (J16)
Pin # Signal Description
1 TX2+
2 TX2-
Analog Twisted Pair Ethernet Transmit Differential Pair. These pins transmit the
serial bit stream for transmission on the Unshielded Twisted Pair Cable (UTP).
These signals interface directly with an isolation transformer.
3 RX2+
6 RX2-
Analog Twisted Pair Ethernet Receive Differential Pair. These pins receive the
serial bit stream from the isolation transformer.
4, 5,
7, 8
CT GND Center Tap Ground – Center taps tied to ground through 75 ohm resistor and
1 nF capacitor.
9 ACT Link/Activity signal indicates a Link is established or Activity is occurring
11 SPEED Speed signal for 10BaseT or 100BaseT transfer rate
10, 12 +VCC LED Power – +3.3 volts for plus side of both LEDs.
Note: The shaded area denotes power or ground.