1.\" Copyright (c) 1986, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)ace.4 8.1 (Berkeley) 06/05/93 7.\" 8.Dd 9.Dt ACE 4 tahoe 10.Os BSD 4.2 11.Sh NAME 12.Nm ace 13.Nd 14.Tn ACC 1510 Mb/s Ethernet interface 16.Sh SYNOPSIS 17.Cd "device ace0 at vba? csr 0xffff0000 flags 0xfff80000 vector acecint acerint" 18.Sh DESCRIPTION 19The 20.Nm ace 21interface provides access to a 10 Mb/s Ethernet network through 22an 23.Tn ACC 24controller. 25.Pp 26The hardware has 32 kilobytes of dual-ported memory on the 27.Tn VERSAbus . 28This memory 29is used for internal buffering by the board, and the interface code reads 30the buffer contents directly through the 31.Tn VERSAbus . 32The address of this memory is given in the 33.Ar flags 34field 35in the configuration file. 36.Pp 37Each of the host's network addresses 38is specified at boot time with an 39.Dv SIOCSIFADDR 40.Xr ioctl 2 . 41The 42.Nm ace 43interface employs the address resolution protocol described in 44.Xr arp 4 45to dynamically map between Internet and Ethernet addresses on the local 46network. 47.Pp 48The interface normally tries to use a 49.Dq trailer 50encapsulation 51to minimize copying data on input and output. 52The use of trailers is negotiated with 53.Tn ARP . 54This negotiation may be disabled, on a per-interface basis, 55by setting the 56.Dv IFF_NOTRAILERS 57flag with an 58.Dv SIOCSIFFLAGS 59.Xr ioctl . 60.Pp 61The device implements an exponential backoff algorithm 62when notified of a collision on the cable. This algorithm utilizes 63a table of random numbers setup by the system at boot time. 64The delay is done in the controller. 65.Sh DIAGNOSTICS 66.Bl -diag 67.It "ace%d: stray xmit interrupt, xnct %d." 68An unexpected transmission complete interrupt was received; 69the interrupt is ignored. 70.It "ace%d: can't handle af%d." 71The interface was handed 72a message with addresses formatted in an unsuitable address 73family; the packet was dropped. 74.El 75.Sh SEE ALSO 76.Xr intro 4 , 77.Xr inet 4 , 78.Xr arp 4 79.Sh HISTORY 80The 81.Nm 82driver appeared in 83.Bx 4.3 tahoe . 84.Sh BUGS 85The hardware is not capable of talking to itself. The software 86implements local sending and broadcast by sending such packets to the 87loop interface. This is a kludge. 88.Pp 89The device doesn't autoconfigure its interrupt vector; it is set 90at 0x90 + eight times the unit number. 91