1LIBIEEE1284(3) Introduction LIBIEEE1284(3)
2
6 libieee1284 - IEEE1284 communications library
7
9 #include <ieee1284.h>
10 cc files... -lieee1284
11
13 The libieee1284 library is a library for accessing parallel port
14 devices.
15 The model presented to the user is fairly abstract: a list of parallel
17 ports with arbitrary names, with functions to access them in various
18 ways ranging from bit operations to block data transfer in one of the
19 IEEE 1284 sanctioned protocols.
20 Although the library resides in user space the speed penalty may not be
22 as bad as you initially think, since the operating system may well
23 provide assistance with block data transfer operations; in fact, the
24 operating system may even use hardware assistance to get the job done.
25 So, using libieee1284, ECP transfers using DMA are possible.
26 The normal sequence of events will be that the application
28 1. calls ieee1284_find_ports to get a list of available ports
29 2. then ieee1284_get_deviceid to look for a device on each port that
30 it is interested in
31 3. and then ieee1284_open to open each port it finds a device it can
32 control on.
33 4. The list of ports returned from ieee1284_find_ports can now be
34 disposed of using ieee1284_free_ports.
35 5. Then when it wants to control the device, it will call
36 ieee1284_claim to prevent other drivers from using the port
37 6. then perhaps do some data transfers
38 7. and then ieee1284_release when it is finished that that particular
39 command. This claim-control-release sequence will be repeated each
40 time it wants to tell the device to do something.
41 8. Finally when the application is finished with the device it will
42 call ieee1284_close.
43 Usually a port needs to be claimed before it can be used. This is to
45 prevent multiple drivers from trampling on each other if they both want
46 to use the same port. The exception to this rule is the collection of
47 IEEE 1284 Device IDs, which has an implicit open-claim-release-close
48 sequence. The reason for this is that it may be possible to collect a
49 Device ID from the operating system, without bothering the device with
50 it.
51
53 When ieee1284_find_ports is first called, the library will look for a
54 configuration file, /etc/ieee1284.conf.
55 Comments begin with a '#' character and extend to the end of the line.
57 Everything else is freely-formatted tokens. A non-quoted (or
58 double-quoted) backslash character '\' preserves the literal value of
59 the next character, and single and double quotes may be used for
60 preserving white-space. Braces and equals signs are recognised as
61 tokens, unless quoted or escaped.
62 The only configuration instruction that is currently recognised is
64 “disallow method ppdev”, for preventing the use of the Linux ppdev
65 driver.
66
68 You can enable debugging output from the library by setting the
69 environment variable LIBIEEE1284_DEBUG to any value.
70
72 /etc/ieee1284.conf
73 Configuration file.
74
76 parport(3), parport_list(3), ieee1284_find_ports(3),
77 ieee1284_free_ports(3), ieee1284_get_deviceid(3), ieee1284_open(3),
78 ieee1284_close(3), ieee1284_claim(3), ieee1284_release(3),
79 ieee1284_data(3), ieee1284_status(3), ieee1284_control(3),
80 ieee1284_negotiation(3), ieee1284_ecp_fwd_to_rev(3),
81 ieee1284_transfer(3), ieee1284_get_irq_fd(3), ieee1284_set_timeout(3)
82
84 Tim Waugh <twaugh@redhat.com>
85 Author.
86
88 Copyright © 2001-2003 Tim Waugh
89 09/18/2007 LIBIEEE1284(3)