| LE(4) | Device Drivers Manual | LE(4) | 
le —
nele0 at isa? port 0x320 irq 9 drq 7 # NE2100
le* at nele?
bicc0 at isa? port 0x320 irq 10 drq 7 # BICC Isolan
le* at bicc?
depca0 at isa? port 0x300 iomem 0xc8000 iosiz 0x8000 irq 5 #
  DEC DEPCA
le* at depca?
le* at isapnp? # ISA Plug-and-Play adapters
depca* at eisa? slot ? # DEC DE422
le* at depca?
le* at mca? slot ? # SKNET Personal/MC2+
le* at pci? dev? function ?
le* at tc? slot ? offset ?
le* at ioasic? offset ?
le* at zbus0
le0 at vme0 irq 4 # BVME410
le0 at vme0 irq 5 # Riebl/PAM
le* at dio? scode ?
le0 at pcc? ipl 3 # MVME147
le0 at hb0 addr 0xe0f00000 ipl 4
le0 at hb0 addr 0xbff80000 level 1
le* at ioasic? offset ?
le* at ibus0 addr ?
le* at sbus? slot ? offset ?
le* at ledma0 slot ? offset ?
le* at lebuffer? slot ? offset ?
le0 at obio0 addr 0x120000 ipl 3
options LANCE_REVC_BUG
le0 at vsbus0 csr 0x200e0000
le interface provides access to a Ethernet network
  via the AMD Am7990 and Am79C90 (CMOS, pin-compatible) LANCE (Local Area
  Network Controller - Ethernet) chip set.
The le driver also supports PCnet-PCI
    cards based on the AMD 79c970 chipset, which is a single-chip implementation
    of a LANCE chip and PCI bus interface.
Each of the host's network addresses is specified at boot time
    with an SIOCSIFADDR
    ioctl(2). The
    le interface employs the Address Resolution Protocol
    (ARP) described in arp(4) to
    dynamically map between Internet and Ethernet addresses on the local
    network.
Selective reception of multicast Ethernet frames is provided by a 64-bit mask; multicast destination addresses are hashed to a bit entry using the Ethernet CRC function.
The use of “trailer” encapsulation to minimize copying data on input and output is supported by the interface but offers no advantage on systems with large page sizes. The use of trailers is automatically negotiated with ARP. This negotiation may be disabled, on a per-interface basis, with ifconfig(8).
le interface supports the following Zorro II
  expansion cards:
The A2065 and Ameristar Ethernet cards support only manual media selection.
The Ariadne card supports a software media selection for its two different connectors:
The Ariadne card uses an autoselect between UTP and BNC, so it uses UTP when an active UTP line is connected or otherwise BNC. See ifmedia(4) for media selection options for ifconfig(8).
le interface
  are:
le
  interface are:
le interface
  are:
No support is provided for switching between media ports. The DECstation 3100 provides both AUI and BNC (thinwire or 10BASE2) connectors. Port selection is via a manual switch and is not software configurable.
The DECstation model 5000/200 PMAD-AA baseboard device provides only a BNC connector.
The ioasic baseboard devices and the
    PMAD-AA TURBOchannel option card provide only an AUI port.
le interface
  include:
Interfaces attached to an ledma0 on SPARC systems typically have two types of connectors:
The appropriate connector can be selected by supplying a
    media parameter to
    ifconfig(8). The supported
    arguments for media are:
If a media parameter is not specified, a
    default connector is selected for use by examining all media types for
    carrier. The first connector on which a carrier is detected will be
    selected. Additionally, if carrier is dropped on a port, the driver will
    switch between the possible ports until one with carrier is found.
TDR is “Time Domain Reflectometry”. The LANCE TDR value is an internal counter of the interval between the start of a transmission and the occurrence of a collision. This value can be used to determine the distance from the Ethernet tap to the point on the Ethernet cable that is shorted or open (unterminated).
le driver allocates buffers large enough to
      receive the maximum size Ethernet packet, this means some other station on
      the LAN transmitted a packet larger than allowed by the Ethernet
    standard.Am79C90 - CMOS Local Area Network Controller for Ethernet, 17881, May 1994, Advanced Micro Devices.
le driver is derived from a
  le driver that first appeared in
  4.4BSD. Support for multiple bus attachments first
  appeared in NetBSD 1.2.
The Amiga le interface first appeared in
    NetBSD 1.0
The Ariadne Ethernet card first appeared with the Amiga ae
    interface in NetBSD 1.1 and was converted to the
    Amiga le interface in NetBSD
    1.3
LANCE_REVC_BUG kernel
  option.
When LANCE_REVC_BUG is enabled, the
    le driver executes one or two calls to an inline
    Ethernet address comparison function for every received packet. On the
    mc68000 it is exactly eight instructions of 16 bits each. There is one
    comparison for each unicast packet, and two comparisons for each broadcast
    packet.
In summary, the cost of the LANCE_REVC_BUG option is:
All sun3 systems are presumed to have this bad revision of the Am7990, until proven otherwise. Alas, the only way to prove what revision of the chip is in a particular system is inspection of the date code on the chip package, to compare against a list of what chip revisions were fabricated between which dates.
Alas, the Am7990 chip is so old that AMD has “de-archived” the production information about it; pending a search elsewhere, we don't know how to identify the revision C chip from the date codes.
On all pmax front-ends, performance is impaired by hardware which
    forces a software copy of packets to and from DMA buffers. The
    ioasic machines and the DECstation 3100 must copy
    packets to and from non-contiguous DMA buffers. The DECstation 5000/200 and
    the PMAD-AA must copy to and from an onboard SRAM DMA buffer. The CPU
    overhead is noticeable, but all machines can sustain full 10 Mb/s media
    speed.
| April 27, 2001 | NetBSD 9.4 |