1.\" Copyright (c) 1997 2.\" Michael Smith 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' 15.\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE 18.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 19.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 20.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 21.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 22.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 23.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 24.\" POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/share/man/man4/ppi.4,v 1.4.2.7 2001/12/17 11:30:12 ru Exp $ 27.\" 28.Dd January 2, 1998 29.Dt PPI 4 30.Os 31.Sh NAME 32.Nm ppi 33.Nd "user-space interface to ppbus parallel 'geek' port" 34.Sh SYNOPSIS 35.Cd "device ppi" 36.Pp 37Minor numbering: Unit numbers correspond directly to ppbus numbers. 38.Sh DESCRIPTION 39The 40.Nm 41driver provides a convenient means for user applications to manipulate the 42state of the parallel port, enabling easy low-speed I/O operations without 43the security problems inherent with the use of the 44.Pa /dev/io 45interface. 46.Sh PROGRAMMING INTERFACE 47.In dev/ppbus/ppi.h 48.In dev/ppbus/ppbconf.h 49.Pp 50All I/O on the 51.Nm 52interface is performed using 53.Fn ioctl 54calls. Each command takes a single 55.Ft u_int8_t 56argument, transferring one byte of data. The following commands are 57available: 58.Bl -tag -width indent 59.It Dv PPIGDATA , PPISDATA 60Get and set the contents of the data register. 61.It Dv PPIGSTATUS , PPISSTATUS 62Get and set the contents of the status register. 63.It Dv PPIGCTRL , PPISCTRL 64Get and set the contents of the control register. 65The following defines correspond to bits in this register. Setting 66a bit in the control register drives the corresponding output low. 67.Bl -tag -width indent -compact 68.It Dv STROBE 69.It Dv AUTOFEED 70.It Dv nINIT 71.It Dv SELECTIN 72.It Dv PCD 73.El 74.It Dv PPIGEPP , PPISEPP 75Get and set the contents of the EPP control register. 76.It Dv PPIGECR , PPISECR 77Get and set the contents of the ECP control register. 78.It Dv PPIGFIFO , PPISFIFO 79Read and write the ECP FIFO (8-bit operations only). 80.El 81.Sh EXAMPLES 82To present the value 0x5a to the data port, drive STROBE low and then high 83again, the following code fragment can be used: 84.Bd -literal -compact 85 86 int fd; 87 u_int8_t val; 88 89 val = 0x5a; 90 ioctl(fd, PPISDATA, &val); 91 ioctl(fd, PPIGCTRL, &val); 92 val |= STROBE; 93 ioctl(fd, PPISCTRL, &val); 94 val &= ~STROBE; 95 ioctl(fd, PPISCTRL, &val); 96 97.Ed 98.Sh BUGS 99The inverse sense of signals is confusing. 100.Pp 101The 102.Fn ioctl 103interface is slow, and there is no way (yet) to chain multiple operations together. 104.Pp 105The headers required for user applications are not installed as part of the 106standard system. 107