Ethernet interface (j2) – Ampro Corporation 420 User Manual
Page 43
Chapter 3
Hardware
CoreModule 420
Reference Manual
37
Ethernet Interface (J2)
The Ethernet solution is provided by the Intel 82559ER PCI controller chip and consists of both the
Media Access Controller (MAC) and the physical layer (PHY) combined into a single component
solution. The 82559ER is a glueless 32-bit PCI controller that features enhanced scatter-gather bus
mastering capabilities, which enables the 82559ER to perform high-speed data transfers over the internal
PCI bus. The 82559ER glueless bus master capabilities enable the component to process high-level
commands and perform multiple operations, thereby off-loading communication tasks from the system
CPU. The Ethernet interface offers the following features:
• Full duplex or half-duplex support
• Full duplex support at 10 Mbps or 100 Mbps
• In full duplex mode the 82559ER adheres to the IEEE 802.3x Flow Control specification.
• In half-duplex mode, performance is enhanced by a proprietary collision reduction mechanism.
• IEEE 802.3 10/100BaseT compatible physical layer to wire transformer
• Two on board LEDs support the speed and the link & activity status
• IEEE 802.3u Auto-Negotiation support
• Fast back-to-back transmission support with minimum interframe spacing (IFS).
• IEEE 802.3x auto-negotiation support for speed and duplex operation
• 3 kB transmit and 3 kB receive FIFOs (helps prevent data underflow and overflow)
• IEEE 802.3x 100BaseTX flow control support
• Onboard magnetics (isolation transformer, U16)
Table 3-16 describes the pin-outs of the Ethernet connector J2.
Table 3-16. Ethernet Interface Pin/Signal Descriptions (J2)
Pin #
Signal
Description
1
TX+
2
TX-
Analog Twisted Pair Ethernet Transmit Differential Pair – These pins transmit the
serial bit stream through the isolation transformer.
3
RX+
6
RX-
Analog Twisted Pair Ethernet Receive Differential Pair – These pins receive the
serial bit stream through the isolation transformer.
4
CT
5
CT
Center Tap – Connected through two 75 ohm resistors in series to center tap of
isolation transformer and then to ground through common 1k PF capacitor.
7
CT
8
CT
Center Tap – Connected through two 75 ohm resistors in series to center tap of
isolation transformer and then to ground through common 1k PF capacitor.
NOTE
The magnetics (isolation transformer, U16) for the Ethernet
connector is included on the CoreModule 420.