1IEEE1284_TRANSFER(3)               Functions              IEEE1284_TRANSFER(3)
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NAME

6       ieee1284_nibble_read, ieee1284_compat_write, ieee1284_byte_read,
7       ieee1284_epp_read_data, ieee1284_epp_write_data,
8       ieee1284_epp_read_addr, ieee1284_epp_write_addr,
9       ieee1284_ecp_read_data, ieee1284_ecp_write_data,
10       ieee1284_ecp_read_addr, ieee1284_ecp_write_addr - data transfer
11       functions
12

SYNOPSIS

14       #include <ieee1284.h>
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16       ssize_t ieee1284_nibble_read(struct parport *port, int flags,
17                                    char *buffer, size_t len);
18
19       ssize_t ieee1284_compat_write(struct parport *port, int flags,
20                                     const char *buffer, size_t len);
21
22       ssize_t ieee1284_byte_read(struct parport *port, int flags,
23                                  char *buffer, size_t len);
24
25       ssize_t ieee1284_epp_read_data(struct parport *port, int flags,
26                                      char *buffer, size_t len);
27
28       ssize_t ieee1284_epp_write_data(struct parport *port, int flags,
29                                       const char *buffer, size_t len);
30
31       ssize_t ieee1284_epp_read_addr(struct parport *port, int flags,
32                                      char *buffer, size_t len);
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34       ssize_t ieee1284_epp_write_addr(struct parport *port, int flags,
35                                       const char *buffer, size_t len);
36
37       ssize_t ieee1284_ecp_read_data(struct parport *port, int flags,
38                                      char *buffer, size_t len);
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40       ssize_t ieee1284_ecp_write_data(struct parport *port, int flags,
41                                       const char *buffer, size_t len);
42
43       ssize_t ieee1284_ecp_read_addr(struct parport *port, int flags,
44                                      char *buffer, size_t len);
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46       ssize_t ieee1284_ecp_write_addr(struct parport *port, int flags,
47                                       const char *buffer, size_t len);
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DESCRIPTION

50       This set of functions is for tranferring bytes in the relevant transfer
51       mode. For ECP and EPP modes two types of transfer are possible: data
52       and address (usually referred to as channel in ECP).
53
54       The supplied port must be a claimed port.
55
56       The supplied buffer must be at least len bytes long. When reading, the
57       transferred data is stored in the buffer; when writing the data to be
58       transferred is taken from the buffer.
59
60       For reads (peripheral to host): if no data is available and
61       F1284_NONBLOCK is not in effect, the inactivity timer is started. If
62       data becomes available before the inactivity time-out elapses it is
63       read; otherwise the return value will be E1284_TIMEDOUT.
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65       For writes (host to peripheral): if the peripheral is not willing to
66       accept data and F1284_NONBLOCK is not in effect, the inactivity timer
67       is started. If the peripheral indicates that it is willing to accept
68       data before the inactivity time-out elapses it is sent; otherwise the
69       return value will be E1284_TIMEDOUT
70
71       The flags may alter the behaviour slightly:
72
73       F1284_NONBLOCK
74           For reads (peripheral to host): if no data is available, return
75           immediately (with E1284_TIMEDOUT).
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77           For writes (host to peripheral): if the peripheral is not willing
78           to accept data, return immediately (with E1284_TIMEDOUT).
79
80       F1284_SWE
81           Don´t use hardware assistance for the transfer, but instead set the
82           parallel port pins according to the wire protocol.
83
84       F1284_RLE (for ECP only)
85           Use run length encoding. If the peripheral is in ECP mode with RLE,
86           calls to ieee1284_ecp_read_data must set this flag in order for the
87           RLE from the peripheral to be interpreted correctly, and calls to
88           ieee1284_ecp_write_data may set this flag in order to take
89           advantage of RLE.
90
91       F1284_FASTEPP (for EPP only)
92           Use multi-byte transfers. Several bytes at a time are transferred
93           using hardware assistance, if supporting hardware is present. The
94           price of this increased speed is that the return value will be less
95           reliable when this flag is used.
96
97       For ECP mode, a given direction is in force at any particular time, and
98       it is up to the application to ensure that it is only writing when in
99       forward mode, and reading when in reverse mode.
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RETURN VALUE

102       The return value is the number of bytes successfully transferred or, if
103       negative, one of:
104
105       E1284_NOTIMPL
106           This transfer mode and flags combination is not yet implemented in
107           libieee1284.
108
109       E1284_TIMEDOUT
110           Timed out waiting for peripheral to handshake.
111
112       E1284_NOMEM
113           Not enough memory is available.
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115       E1284_SYS
116           There was a problem at the operating system level. The global
117           variable errno has been set appropriately.
118
119       E1284_INVALIDPORT
120           The port parameter is invalid (for instance, perhaps the port is
121           not claimed).
122
123       If any bytes are successfully transferred, that number is returned. An
124       error is returned only if no bytes are transferred.
125
126       For host-to-peripheral transfers, all data is at the peripheral by the
127       time the call returns.
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SEE ALSO

130       ieee1284_ecp_fwd_to_rev(3)
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AUTHOR

133       Tim Waugh <twaugh@redhat.com>
134           Author.
135

137       Copyright © 2001-2003 Tim Waugh
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141[FIXME: source]                   07/22/2010              IEEE1284_TRANSFER(3)
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