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.Dd January 2, 1998 27.Dt PPI 4 28.Os 29.Sh NAME 30.Nm ppi 31.Nd "user-space interface to ppbus parallel 'geek' port" 32.Sh SYNOPSIS 33.Cd "device ppi" 34.Pp 35Minor numbering: unit numbers correspond directly to ppbus numbers. 36.Pp 37.In dev/ppbus/ppi.h 38.In dev/ppbus/ppbconf.h 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 48All I/O on the 49.Nm 50interface is performed using 51.Fn ioctl 52calls. 53Each command takes a single 54.Ft uint8_t 55argument, transferring one byte of data. 56The following commands are available: 57.Bl -tag -width indent 58.It Dv PPIGDATA , PPISDATA 59Get and set the contents of the data register. 60.It Dv PPIGSTATUS , PPISSTATUS 61Get and set the contents of the status register. 62.It Dv PPIGCTRL , PPISCTRL 63Get and set the contents of the control register. 64The following defines correspond to bits in this register. 65Setting a bit in the control register drives the corresponding output low. 66.Bl -tag -width indent -compact 67.It Dv STROBE 68.It Dv AUTOFEED 69.It Dv nINIT 70.It Dv SELECTIN 71.It Dv PCD 72.El 73.It Dv PPIGEPP , PPISEPP 74Get and set the contents of the EPP control register. 75.It Dv PPIGECR , PPISECR 76Get and set the contents of the ECP control register. 77.It Dv PPIGFIFO , PPISFIFO 78Read and write the ECP FIFO (8-bit operations only). 79.El 80.Sh EXAMPLES 81To present the value 0x5a to the data port, drive STROBE low and then high 82again, the following code fragment can be used: 83.Bd -literal -compact 84 85 int fd; 86 uint8_t val; 87 88 val = 0x5a; 89 ioctl(fd, PPISDATA, &val); 90 ioctl(fd, PPIGCTRL, &val); 91 val |= STROBE; 92 ioctl(fd, PPISCTRL, &val); 93 val &= ~STROBE; 94 ioctl(fd, PPISCTRL, &val); 95 96.Ed 97.Sh BUGS 98The inverse sense of signals is confusing. 99.Pp 100The 101.Fn ioctl 102interface is slow, and there is no way (yet) to chain multiple operations together. 103.Pp 104The headers required for user applications are not installed as part of the 105standard system. 106