1IEEE1284_DATA(3)                   Functions                  IEEE1284_DATA(3)
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NAME

6       ieee1284_read_data, ieee1284_write_data, ieee1284_data_dir,
7       ieee1284_wait_data - control the data lines
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SYNOPSIS

10       #include <ieee1284.h>
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12       int ieee1284_read_data(struct parport *port);
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14       void ieee1284_write_data(struct parport *port, unsigned char dt);
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16       int ieee1284_data_dir(struct parport *port, int reverse);
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18       int ieee1284_wait_data(struct parport *port, unsigned char mask,
19                              unsigned char val, struct timeval *timeout);
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DESCRIPTION

22       These functions manipulate the data lines of the parallel port
23       associated with port (which must have been claimed using
24       ieee1284_claim(3)). The lines are represented by an 8-bit number (one
25       line per bit) and a direction. The data lines are driven as a group;
26       they may be all host-driven (forward direction) or not (reverse
27       direction). When the peripheral is driving them the host must not.
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29       For ieee1284_data_dir the reverse parameter should be zero to turn the
30       data line drivers on and non-zero to turn them off. Some port types may
31       be unable to switch off the data line drivers.
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33       Setting the data lines may have side effects on some port types (for
34       example, some Amiga ports pulse nStrobe).
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36       ieee1284_wait_data waits, up until the timeout, for the data bits
37       specified in mask to have the corresponding values in val.
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RETURN VALUE

40       ieee1284_read_data returns the 8-bit number representing the data lines
41       unless it is not possible to return such a value with this port type,
42       in which case it returns an error code. Possible error codes:
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44       E1284_NOTAVAIL
45           Bi-directional data lines are not available on this system.
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47       E1284_INVALIDPORT
48           The port parameter is invalid (perhaps it has not been claimed, for
49           instance).
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51       E1284_SYS
52           There was an error at the operating system level, and errno has
53           been set accordingly.
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55       E1284_TIMEDOUT
56           The timeout has elapsed.
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58       Whereas ieee1284_read_data may return E1284_NOTAVAIL on its first
59       invocation on the port, if it does not do so then it cannot until
60       ieee1284_close is called for that port.
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AUTHOR

63       Tim Waugh <twaugh@redhat.com>
64           Author.
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67       Copyright © 2001-2003 Tim Waugh
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71[FIXME: source]                   07/22/2010                  IEEE1284_DATA(3)
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