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