1*47673Scael.\" Copyright (c) 1986, 1991 The Regents of the University of California. 236754Sbostic.\" All rights reserved. 330226Ssam.\" 443580Strent.\" %sccs.include.redist.man% 530226Ssam.\" 6*47673Scael.\" @(#)ace.4 6.5 (Berkeley) 03/27/91 736754Sbostic.\" 8*47673Scael.Dd 9*47673Scael.Dt ACE 4 tahoe 10*47673Scael.Os BSD 4.2 11*47673Scael.Sh NAME 12*47673Scael.Nm ace 13*47673Scael.Nd 14*47673Scael.Tn ACC 15*47673Scael10 Mb/s Ethernet interface 16*47673Scael.Sh SYNOPSIS 17*47673Scael.Cd "device ace0 at vba? csr 0xffff0000 flags 0xfff80000 vector acecint acerint" 18*47673Scael.Sh DESCRIPTION 1930226SsamThe 20*47673Scael.Nm ace 2130226Ssaminterface provides access to a 10 Mb/s Ethernet network through 22*47673Scaelan 23*47673Scael.Tn ACC 24*47673Scaelcontroller. 25*47673Scael.Pp 26*47673ScaelThe hardware has 32 kilobytes of dual-ported memory on the 27*47673Scael.Tn VERSAbus . 2830226SsamThis memory 2930226Ssamis used for internal buffering by the board, and the interface code reads 30*47673Scaelthe buffer contents directly through the 31*47673Scael.Tn VERSAbus . 32*47673ScaelThe address of this memory is given in the 33*47673Scael.Ar flags 34*47673Scaelfield 3530226Ssamin the configuration file. 36*47673Scael.Pp 3730226SsamEach of the host's network addresses 38*47673Scaelis specified at boot time with an 39*47673Scael.Dv SIOCSIFADDR 40*47673Scael.Xr ioctl 2 . 41*47673ScaelThe 42*47673Scael.Nm ace 4330226Ssaminterface employs the address resolution protocol described in 44*47673Scael.Xr arp 4 4530226Ssamto dynamically map between Internet and Ethernet addresses on the local 4630226Ssamnetwork. 47*47673Scael.Pp 48*47673ScaelThe interface normally tries to use a 49*47673Scael.Dq trailer 50*47673Scaelencapsulation 5130226Ssamto minimize copying data on input and output. 52*47673ScaelThe use of trailers is negotiated with 53*47673Scael.Tn ARP . 5430226SsamThis negotiation may be disabled, on a per-interface basis, 55*47673Scaelby setting the 56*47673Scael.Dv IFF_NOTRAILERS 57*47673Scaelflag with an 58*47673Scael.Dv SIOCSIFFLAGS 59*47673Scael.Xr ioctl . 60*47673Scael.Pp 6130226SsamThe device implements an exponential backoff algorithm 6230226Ssamwhen notified of a collision on the cable. This algorithm utilizes 6330226Ssama table of random numbers setup by the system at boot time. 6430226SsamThe delay is done in the controller. 65*47673Scael.Sh DIAGNOSTICS 66*47673Scael.Bl -diag 67*47673Scael.It "ace%d: stray xmit interrupt, xnct %d." 6830226SsamAn unexpected transmission complete interrupt was received; 6930226Ssamthe interrupt is ignored. 70*47673Scael.It "ace%d: can't handle af%d." 7130226SsamThe interface was handed 7230226Ssama message with addresses formatted in an unsuitable address 7330226Ssamfamily; the packet was dropped. 74*47673Scael.El 75*47673Scael.Sh SEE ALSO 76*47673Scael.Xr intro 4 , 77*47673Scael.Xr inet 4 , 78*47673Scael.Xr arp 4 79*47673Scael.Sh HISTORY 80*47673ScaelThe 81*47673Scael.Nm 82*47673Scaeldriver appeared in 83*47673Scael.Bx 4.3 tahoe . 84*47673Scael.Sh BUGS 8530226SsamThe hardware is not capable of talking to itself. The software 8630226Ssamimplements local sending and broadcast by sending such packets to the 8730226Ssamloop interface. This is a kludge. 88*47673Scael.Pp 8930226SsamThe device doesn't autoconfigure its interrupt vector; it is set 9030226Ssamat 0x90 + eight times the unit number. 91