NSPHY(4) BSD Programmer's Manual NSPHY(4)NAMENSPHY - Physical layer (PHY) driver for National Semiconductor DP83840
SYNOPSIS
nsphy* at de? phy ?
nsphy* at exp? phy ?
DESCRIPTION
The nsphy driver supports the National Semiconductor DP83840 Physical
Layer device (PHY) for 10 and 100 Mb/s Ethernet. This device driver is
called upon by network device drivers; no direct administrative control
is provided.
The ifconfig(8) command in conjunction with the device driver making us-
ing of this drivers services provides an administrative interface that
allows various physical level parameters (such as duplex, speed, and
loopback) to be controlled.
The DP83840 supports NWay automatic speed and duplex negotiation as well
as automatic speed detection for hubs that do not support the NWay FLP
protocol (both methods are defined by the IEEE 802.3u standard).
SEE ALSOifconfig(8), de(4), exp(4)BUGS
The DP83840 does not natively detect a speed switch from 100 Mb/s to 10
Mb/s by the hub; the NSPHY driver attempts to monitor traffic and force
the device to renegotiate speed when no traffic is present - this mecha-
nism can cause small (10ms or less) delays every 5 seconds or so when the
network interface is not plugged in.
4th Berkeley Distribution December 13, 1996 1
