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.\" $FreeBSD$ 27.\" 28.Dd January 2, 1998 29.Dt PPI 4 30.Os FreeBSD 31.Sh NAME 32.Nm ppi 33.Nd 34user-space interface to ppbus parallel 'geek' port 35.Sh SYNOPSIS 36.Cd "device ppi0 at ppbus? 37.sp 38Minor numbering: Unit numbers correspond directly to ppbus numbers. 39.Sh DESCRIPTION 40The 41.Nm 42driver provides a convenient means for user applications to manipulate the 43state of the parallel port, enabling easy low-speed I/O operations without 44the security problems inherent with the use of the 45.Pa /dev/io 46interface. 47.Sh PROGRAMMING INTERFACE 48.Pp 49.Fd #include </sys/dev/ppbus/ppi.h> 50.Fd #include </sys/dev/ppbus/ppbconf.h> 51.Pp 52All I/O on the 53.Nm 54interface is performed using 55.Fn ioctl 56calls. Each command takes a single 57.Ty u_int8_t 58argument, transferring one byte of data. The following commands are 59available: 60.Bl -tag -width 10 61.It PPIGDATA, PPISDATA 62Get and set the contents of the data register. 63.It PPIGSTATUS, PPISSTATUS 64Get and set the contents of the status register. 65.It PPIGCTRL, PPISCTRL 66Get and set the contents of the control register. 67The following defines correspond to bits in this register. Setting 68a bit in the control register drives the corresponding output low. 69.Bl -tag -width 10 -compact 70.It STROBE 71.It AUTOFEED 72.It nINIT 73.It SELECTIN 74.It PCD 75.El 76.It PPIGEPP, PPISEPP 77Get and set the contents of the EPP control register. 78.It PPIGECR, PPISECR 79Get and set the contents of the ECP control register. 80.It PPIGFIFO, PPISFIFO 81Read and write the ECP FIFO (8-bit operations only). 82.El 83.Sh EXAMPLES 84To present the value 0x5a to the data port, drive STROBE low and then high 85again, the following code fragment can be used: 86.Bd -literal -compact 87 88 int fd; 89 u_int8_t val; 90 91 val = 0x5a; 92 ioctl(fd, PPISDATA, &val); 93 ioctl(fd, PPIGCTRL, &val); 94 val |= STROBE; 95 ioctl(fd, PPISCTRL, &val); 96 val &= ~STROBE; 97 ioctl(fd, PPISCTRL, &val); 98 99.Ed 100.Sh BUGS 101The inverse sense of signals is confusing. 102.Pp 103The 104.Fn ioctl 105interface is slow, and there is no way (yet) to chain multiple operations together. 106.Pp 107The headers required for user applications are not installed as part of the 108standard system. 109