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- Committer: Bazaar Package Importer
- Author(s): David Schleef
- Date: 2003-09-23 18:11:12 UTC
- Revision ID: james.westby@ubuntu.com-20030923181112-sat05jyh702rb1at
Tags: upstream-0.7.21
Import upstream version 0.7.21
- files added:
- comedi_calibrate
- comedi_calibrate/results
- comedi_config
- debian
- demo
- doc
- doc/html
- doc/man
- etc
- etc/pcmcia
- include
- lib
- m4
- man
- python
- testing
added
removed
doc/funcref
1
Function: comedi_close -- close a Comedi device
2
Retval: int
3
Param: comedi * device
4
Description:
5
Close a device previously opened by comedi_open().
6
Returns:
7
If sucessful, comedi_close returns 0. On failure, -1 is returned.
8
9
Function: comedi_open -- open a Comedi device
10
Retval: comedi_t *
11
Param: const char * filename
12
Description:
13
Open a Comedi device specified by the file filename.
14
Returns:
15
If sucessful, comedi_open returns a pointer to a valid comedi_t
16
structure. This structure is transparent; the pointer should not
17
be dereferenced by the application. NULL is returned on failure.
18
19
Function: comedi_loglevel -- change Comedilib logging properties
20
Retval: int
21
Param: int loglevel
22
Description:
23
This function affects the output of debugging and error messages
24
from Comedilib. By increasing the loglevel, additional debugging
25
information will be printed. Error and debugging messages are
26
printed to the stream stderr.
27
28
The default loglevel can be set by using the environment variable
29
COMEDI_LOGLEVEL. The default loglevel is 1.
30
31
In order to conserve resources, some debugging information is
32
disabled by default when Comedilib is compiled.
33
34
The meaning of the loglevels is as follows:
35
36
COMEDI_LOGLEVEL=0 Comedilib prints nothing.
37
38
COMEDI_LOGLEVEL=1 (default) Comedilib prints error messages when
39
there is a self-consistency error (i.e., an internal bug.)
40
41
COMEDI_LOGLEVEL=2 Comedilib prints an error message when an invalid
42
parameter is passed.
43
44
COMEDI_LOGLEVEL=3 Comedilib prints an error message whenever an
45
error is generated in the Comedilib library or in the C library,
46
when called by Comedilib.
47
48
COMEDI_LOGLEVEL=4 Comedilib prints a lot of junk.
49
Returns:
50
This function returns the previous loglevel.
51
52
Function: comedi_perror -- print a Comedilib error message
53
Retval: void
54
Param: const char * s
55
Description:
56
When a Comedilib function fails, it usually returns -1 or
57
NULL, depending on the return type. An internal library
58
variable stores an error number, which can be retrieved with
59
comedi_errno(). This error number can be converted to a
60
human-readable form by the functions comedi_perror()
61
and comedi_strerror().
62
63
These functions are intended to mimic the behavior of the
64
standard C library functions perror(), strerror(), and errno.
65
In particular, Comedilib functions sometimes return an error
66
that is generated inside the C library; the comedi error
67
message in this case is the same as the C library.
68
69
The function comedi_perror() prints an error message to stderr.
70
The error message consists of the argument string, a colon, a
71
space, a description of the error condition, and a new line.
72
73
Function: comedi_strerror -- return string describing Comedilib error code
74
Retval: char *
75
Param: int errnum
76
Description:
77
When a Comedilib function fails, it usually returns -1 or
78
NULL, depending on the return type. An internal library
79
variable stores an error number, which can be retrieved with
80
comedi_errno(). This error number can be converted to a
81
human-readable form by the functions comedi_perror()
82
and comedi_strerror().
83
84
These functions are intended to mimic the behavior of the
85
standard C library functions perror(), strerror(), and errno.
86
In particular, Comedilib functions sometimes return an error
87
that is generated inside the C library; the comedi error
88
message in this case is the same as the C library.
89
90
The function comedi_strerror() returns a pointer to a
91
character string
92
describing the Comedilib error errnum. The persistence
93
of the returned pointer is undefined, and should not be trusted
94
after the next Comedilib call. An unrecognized error number will
95
return a pointer to the string "undefined error", or similar.
96
97
Function: comedi_errno -- number of last Comedilib error
98
Retval: int
99
Param: void
100
Description:
101
When a Comedilib function fails, it usually returns -1 or
102
NULL, depending on the return type. An internal library
103
variable stores an error number, which can be retrieved with
104
comedi_errno(). This error number can be converted to a
105
human-readable form by the functions comedi_perror()
106
and comedi_strerror().
107
108
These functions are intended to mimic the behavior of the
109
standard C library functions perror(), strerror(), and errno.
110
In particular, Comedilib functions sometimes return an error
111
that is generated inside the C library; the comedi error
112
message in this case is the same as the C library.
113
114
The function comedi_errno() returns an integer describing
115
the most recent comedilib error. This integer may be used
116
as the errnum parameter for comedi_strerror().
117
118
Note that comedi_errno() is deliberately different than the
119
variable errno. This is to overcome difficulties in making
120
errno thread-safe.
121
122
Function: comedi_fileno -- integer descriptor of Comedilib device
123
Retval: int
124
Param: comedi_t * device
125
Description:
126
The function comedi_fileno returns the integer descriptor for
127
the device dev. This descriptor can then be used as the
128
file descriptor parameter of read(), write(), etc.
129
This function is intended to mimic the standard C library
130
function fileno(). If dev is an invalid comedi_t
131
pointer, the function returns -1 and sets the appropriate
132
Comedilib error value.
133
134
Function: comedi_get_n_subdevices -- number of subdevices
135
Retval: int
136
Param: comedi_t * device
137
Description:
138
Returns the number of subdevices belonging to the Comedi
139
device referenced by the parameter device.
140
141
Function: comedi_get_version_code -- Comedi version code
142
Retval: int
143
Param: comedi_t * device
144
Description:
145
Returns the Comedi kernel module version code. A valid Comedi
146
device referenced by the parameter device is necessary to
147
communicate with the kernel module. On error, -1 is returned.
148
149
The version code is encoded as a bitfield of three 8-bit
150
numbers. For example, 0x00073d is the version code for
151
version 0.7.61.
152
153
This function is of limited usefulness. A typical
154
mis-application of this function is to use it to determine
155
if a certain feature is supported. If the application needs
156
to know of the existence of a particular feature, an existence
157
test function should be written and put in the Comedilib source.
158
159
Function: comedi_get_driver_name -- Comedi driver name
160
Retval: char *
161
Param: comedi_t * device
162
Description:
163
The function comedi_get_driver_name returns a pointer
164
to a string containing the name of the driver being used by comedi
165
for the comedi device represented by device. This pointer is
166
valid until the device is closed. This function returns NULL
167
if there is an error.
168
169
Function: comedi_get_board_name -- Comedi device name
170
Retval: char *
171
Param: comedi_t * device
172
Description:
173
The function comedi_get_board_name returns a pointer
174
to a string containing the name of the device. This pointer is
175
valid until the comedi descriptor it is closed. This
176
function returns NULL if there is an error.
177
178
Function: comedi_get_subdevice_type -- type of subdevice
179
Retval: int
180
Param: comedi_t * device
181
Param: unsigned int subdevice
182
Description:
183
The function comedi_get_subdevice_type() returns an
184
integer describing the type of subdevice that belongs to the comedi
185
device device and has the index subdevice. The
186
function returns -1 if there is an error.
187
188
XXX Subdevice type table
189
190
Function: comedi_find_subdevice_by_type -- search for subdevice type
191
Retval: int
192
Param: comedi_t * device
193
Param: int type
194
Param: unsigned int start_subdevice
195
Description:
196
The function comedi_find_subdevice_by_type() tries to
197
locate a subdevice belonging to comedi device device,
198
having type type, starting with the subdevice
199
start_subdevice. If it finds a subdevice with the requested
200
type, it returns its index. If it does not locate the requested
201
subdevice, it returns -1 and sets the Comedilib error number to
202
XXX "subdevice not found". If there is an error, the function
203
returns -1 and sets the appropriate error.
204
205
Function: comedi_get_read_subdevice -- find streaming input subdevice
206
Retval: int
207
Param: comedi_t * device
208
Description:
209
The function comedi_get_read_subdevice() returns the subdevice
210
that allows streaming input for device dev. If no subdevice
211
supports streaming input, -1 is returned and the Comedilib error
212
number is set to XXX "subdevice not found".
213
214
Function: comedi_get_write_subdevice -- find streaming output subdevice
215
Retval: int
216
Param: comedi_t * device
217
Description:
218
The function comedi_get_write_subdevice() returns the subdevice
219
that allows streaming output for device dev. If no subdevice
220
supports streaming output, -1 is returned and the Comedilib error
221
number is set to XXX "subdevice not found".
222
223
Function: comedi_get_subdevice_flags -- properties of subdevice
224
Retval: int
225
Param: comedi_t * device
226
Param: unsigned int subdevice
227
Description:
228
This function returns a bitfield describing the capabilities of
229
the specified subdevice. If there is an error, -1 is returned,
230
and the Comedilib error value is set.
231
232
XXX table.
233
234
Function: comedi_get_n_channels -- number of subdevice channels
235
Retval: int
236
Param: comedi_t * device
237
Param: unsigned int subdevice
238
Description:
239
The function comedi_get_n_channels() returns the number
240
of channels of the subdevice belonging to the comedi device device
241
and having index subdevice. This function returns -1 on error and
242
the Comedilib error value is set.
243
244
Function: comedi_range_is_chan_specific -- range information depends on channel
245
Retval: int
246
Param: comedi_t * device
247
Param: unsigned int subdevice
248
Description:
249
If each channel of the specified subdevice has different range
250
information, this function returns 1. Otherwise, this function
251
returns 0. On error, this function returns -1.
252
253
Function: comedi_maxdata_is_chan_specific -- maximum sample depends on channel
254
Retval: int
255
Param: comedi_t * device
256
Param: unsigned int subdevice
257
Description:
258
If each channel of the specified subdevice has different maximum
259
sample values, this function returns 1. Otherwise, this function
260
returns 0. On error, this function returns -1.
261
262
Function: comedi_get_maxdata -- maximum sample of channel
263
Retval: lsampl_t
264
Param: comedi_t * device
265
Param: unsigned int subdevice
266
Param: unsigned int channel
267
Description:
268
The function comedi_get_maxdata() returns the maximum
269
valid data value for channel chan of subdevice
270
subdevice belonging to the comedi device device
271
This function returns 0 on error.
272
273
Function: comedi_get_n_ranges -- number of ranges of channel
274
Retval: int
275
Param: comedi_t * device
276
Param: unsigned int subdevice
277
Param: unsigned int channel
278
Description:
279
The function comedi_get_n_ranges() returns the number
280
of ranges of the channel chan belonging to the subdevice
281
of the comedi device device. This function returns -1 on error.
282
283
Function: comedi_get_range -- range information of channel
284
Retval: comedi_range *
285
Param: comedi_t * device
286
Param: unsigned int subdevice
287
Param: unsigned int channel
288
Param: unsigned int range
289
Description:
290
The function comedi_get_range() returns a pointer to a
291
comedi_range structure that contains information that can be used to
292
convert sample values to or from physical units. The pointer is valid
293
until the Comedi device device is closed. If there is an
294
error, NULL is returned.
295
296
Function: comedi_find_range -- search for range
297
Retval: int
298
Param: comedi_t * device
299
Param: unsigned int subdevice
300
Param: unsigned int channel
301
Param: unsigned int unit
302
Param: double min
303
Param: double max
304
Description:
305
The function comedi_find_range() tries to
306
locate the optimal (smallest) range for the channel chan
307
belonging to a subdevice of the comedi device device,
308
that includes both min and max in units.
309
If a matching range is found, the index of the matching range is
310
returned. If no matching range is available, the function returns
311
-1.
312
313
Function: comedi_get_buffer_size -- streaming buffer size of subdevice
314
Retval: int
315
Param: comedi_t * device
316
Param: unsigned int subdevice
317
Description:
318
The function comedi_get_buffer_size() returns the size (in bytes)
319
of the streaming buffer for the subdevice specified by device and
320
subdevice. On error, -1 is returned.
321
322
Function: comedi_get_max_buffer_size -- maximum streaming buffer size
323
Retval: int
324
Param: comedi_t * device
325
Param: unsigned int subdevice
326
Description:
327
The function comedi_get_max_buffer_size() returns the maximum
328
allowable size (in bytes) of the streaming buffer for the subdevice
329
specified by device and subdevice. Changing the maximum buffer
330
size requires appropriate privileges. On error, -1 is returned.
331
332
Function: comedi_set_buffer_size -- streaming buffer size of subdevice
333
Retval: int
334
Param: comedi_t * device
335
Param: unsigned int subdevice
336
Param: unsigned int size
337
Description:
338
The function comedi_set_buffer_size() changes the size of the
339
streaming buffer for the subdevice specified by device and subdevice.
340
The parameter size must be a multiple of the virtual memory page
341
size.
342
343
The virtual memory page size can be determined using
344
sysconf(_SC_PAGE_SIZE).
345
346
Function: comedi_trigger -- perform streaming input/output (deprecated)
347
Retval: int
348
Param: comedi_t * device
349
Param: comedi_trig * trig
350
Status: deprecated
351
Description:
352
The function comedi_trigger() instructs Comedi to
353
perform the command specified by the trigger structure trig.
354
The return value depends on
355
the particular trig being issued. If there is an
356
error, -1 is returned.
357
358
Function: comedi_do_insnlist -- perform multiple instructions
359
Retval: int
360
Param: comedi_t * device
361
Param: comedi_insnlist * list
362
Description:
363
The function comedi_do_insnlist() performs multiple Comedi
364
instructions as part of one system call. In addition, Comedi
365
attempts to perform the instructions atomically, that is, on
366
standard Linux kernels, no process preemption should occur
367
during the instructions. However, the process may be preempted
368
before or after the group of instructions.
369
370
This function can be used to avoid the overhead of multiple
371
system calls, or to ensure that multiple instructions occur
372
without significant delay between them.
373
374
Preemption may occur if any of the instructions or the data
375
arrays of any of the instructions exist in non-resident or
376
copy-on-write pages.
377
Returns:
378
The function comedi_do_insnlist() returns the number of
379
sucessfully completed instructions. Error information for
380
the unsucessful instruction is not available. If there is
381
an error before the first instruction can be executed, -1
382
is returned.
383
384
Function: comedi_do_insn -- perform instruction
385
Retval: int
386
Param: comedi_t * device
387
Param: comedi_insn * instruction
388
Description:
389
The function comedi_do_insn() performs a single instruction.
390
If sucessful, comedi_do_insn() returns the number of samples
391
measured, which may be less than the number of requested
392
samples. Comedi limits the number of requested samples in
393
order to enforce fairness among processes. If there is an
394
error, -1 is returned.
395
396
Function: comedi_lock -- subdevice reservation
397
Retval: int
398
Param: comedi_t * device
399
Param: unsigned int subdevice
400
Description:
401
The function comedi_lock() reserves a subdevice for use by the
402
current process. While the lock is held, no other process is
403
allowed to read, write, or configure that subdevice, although
404
other processes can read information about the subdevice. The
405
lock is released when comedi_unlock() is called, or the device
406
is closed. If sucessful, 0 is returned. If there is an error,
407
-1 is returned.
408
409
Function: comedi_unlock -- subdevice reservation
410
Retval: int
411
Param: comedi_t * device
412
Param: unsigned int subdevice
413
Description:
414
The function comedi_unlock() released a subdevice lock acquired
415
by comedi_lock(). If sucessful, 0 is returned, otherwise -1.
416
417
Function: comedi_to_phys -- convert sample to physical units
418
Retval: double
419
Param: lsampl_t data
420
Param: comedi_range * range
421
Param: lsampl_t maxdata
422
Description:
423
Converts data given in sample values (lsampl_t, between 0 and
424
maxdata) into physical units (double). The parameter range
425
represents the conversion information to use, and the parameter
426
maxdata represents the maximum possible data value for the
427
channel that the data was read.
428
429
Conversion of endpoint sample values, that is, sample values
430
equal to 0 or maxdata, is affected by the Comedilib out-of-range
431
behavior. If the out-of-range behavior is set to COMEDI_OOR_NAN,
432
endpoint values are converted to NAN. If the out-of-range
433
behavior is set to COMEDI_OOR_NUMBER, the endpoint values are
434
converted similarly to other values.
435
436
If there is an error, NAN is returned.
437
438
Function: comedi_from_phys -- convert physical units to sample
439
Retval: lsampl_t
440
Param: double data
441
Param: comedi_range * range
442
Param: lsampl_t maxdata
443
Description:
444
Converts data given in physical units (data) into sample values
445
(lsampl_t, between 0 and maxdata). The parameter rng
446
represents the conversion information to use, and the parameter
447
maxdata represents the maximum possible data value for the
448
channel that the data will be written to.
449
450
Conversion is not affected by out-of-range behavior. Out-of-range
451
data parameters are silently truncated to the range 0 to maxdata.
452
453
Function: comedi_data_read -- read single sample from channel
454
Retval: int
455
Param: comedi_t * device
456
Param: unsigned int subdevice
457
Param: unsigned int channel
458
Param: unsigned int range
459
Param: unsigned int aref
460
Param: lsampl_t * data
461
Description:
462
Reads a single sample on the channel specified by the Comedi
463
device device, the subdevice subdevice, and the channel channel.
464
For the A/D conversion (if appropriate),
465
the device is configured to use range specification
466
range and (if appropriate) analog reference type
467
aref. Analog reference types that are not supported
468
by the device are silently ignored.
469
470
The function comedi_data_read() reads one data value from
471
the specified channel and places the data value in the
472
location pointed to by data.
473
474
WARNING: comedi_data_read() does not do any pausing to
475
allow multiplexed analog inputs to settle before
476
performing an analog to digital conversion. If you are
477
switching between different channels and need to allow
478
your analog input to settle for an accurate reading,
479
use comedi_data_read_delayed(), or set the
480
input channel at an earlier time with
481
comedi_data_read_hint().
482
483
On sucess, comedi_data_read() returns 1 (the number of samples
484
read). If there is an error, -1 is returned.
485
486
Data values returned by this function are unsigned integers
487
less than or equal to the maximum sample value of the channel,
488
which can be determined using the function comedi_get_maxdata().
489
Conversion of data values to physical units can be performed
490
by the function comedi_to_phys().
491
492
Function: comedi_data_read_delayed -- read single sample from channel after delaying for specified settling time
493
Retval: int
494
Param: comedi_t * device
495
Param: unsigned int subdevice
496
Param: unsigned int channel
497
Param: unsigned int range
498
Param: unsigned int aref
499
Param: lsampl_t * data
500
Param: unsigned int nanosec
501
Description:
502
Similar to comedi_data_read() except it will wait for the
503
specified number of nanoseconds between setting the input
504
channel and taking a sample. For analog inputs, most
505
boards have a single
506
analog to digital converter which is multiplexed to be
507
able to read multiple channels. If the input is not allowed
508
to settle after the multiplexer switches channels, the
509
reading will be inaccurate. This function is useful
510
for allowing a multiplexed analog input to settle
511
when switching channels.
512
513
Although the settling time is specified in nanoseconds, the
514
actual settling time will be rounded up to the nearest
515
microsecond.
516
517
Function: comedi_data_read_hint -- tell driver which channel/range/aref you are going to read from next
518
Retval: int
519
Param: comedi_t * device
520
Param: unsigned int subdevice
521
Param: unsigned int channel
522
Param: unsigned int range
523
Param: unsigned int aref
524
Description:
525
Used to prepare an analog input for a subsequent call to
526
comedi_data_read(). It is not necessary to use this
527
function, but it can be useful for eliminating inaccuaracies
528
caused by insufficient settling times when switching the
529
channel
530
or gain on an analog input. This function sets an analog input
531
to the channel, range, and aref specified but does not
532
perform an actual analog to digital conversion.
533
534
Alternatively, one can simply use comedi_data_read_delayed(),
535
which sets up the
536
input, pauses to allow settling, then performs a conversion.
537
538
Function: comedi_data_write -- write single sample to channel
539
Retval: int
540
Param: comedi_t * device
541
Param: unsigned int subdevice
542
Param: unsigned int channel
543
Param: unsigned int range
544
Param: unsigned int aref
545
Param: lsampl_t data
546
Description:
547
Writes a single sample on the channel that is specified by the
548
Comedi device device, the subdevice subdevice, and the channel
549
channel. If appropriate, the device is configured to use range
550
specification range and analog reference type aref. Analog
551
reference types that are not supported by the device are
552
silently ignored.
553
554
The function comedi_data_write() writes the data value specified
555
by the parameter data to the specified channel.
556
557
On sucess, comedi_data_write() returns 1 (the number of samples
558
written). If there is an error, -1 is returned.
559
560
Function: comedi_dio_config -- change input/output properties of channel
561
Retval: int
562
Param: comedi_t * device
563
Param: unsigned int subdevice
564
Param: unsigned int channel
565
Param: unsigned int direction
566
Description:
567
The function comedi_dio_config() configures individual channels
568
in a digital I/O subdevice to be either input or output, depending
569
on the value of parameter direction. Valid directions are
570
COMEDI_INPUT or COMEDI_OUTPUT.
571
572
Depending on the capabilities of the hardware device, multiple
573
channels may be grouped together to determine direction. In this
574
case, a single call to comedi_dio_config() for any channel in the
575
group will affect the entire group.
576
577
If sucessful, 1 is returned, otherwise -1.
578
579
Function: comedi_dio_read -- read single bit from digital channel
580
Retval: int
581
Param: comedi_t * device
582
Param: unsigned int subdevice
583
Param: unsigned int channel
584
Param: unsigned int * bit
585
Description:
586
The function reads the channel channel belonging to the
587
subdevice subdevice of device device. The data value that is
588
read is stored in the location pointed to by bit. This function
589
is equivalent to comedi_data_read(device,subdevice,channel,0,0,bit).
590
This function does not require a digital subdevice or a subdevice
591
with a maximum data value of 1 to work properly.
592
593
Return values and errors are the same as comedi_data_read().
594
595
Function: comedi_dio_write -- write single bit to digital channel
596
Retval: int
597
Param: comedi_t * device
598
Param: unsigned int subdevice
599
Param: unsigned int channel
600
Param: unsigned int bit
601
Description:
602
The function writes the value bit to the channel channel belonging
603
to the subdevice subdevice of device device. This function
604
is equivalent to comedi_data_write(device,subdevice,channel,0,0,bit).
605
This function does not require a digital subdevice or a subdevice
606
with a maximum data value of 1 to work properly.
607
608
Return values and errors are the same as comedi_data_write().
609
610
Function: comedi_dio_bitfield -- read/write multiple digital channels
611
Retval: int
612
Param: comedi_t * device
613
Param: unsigned int subdevice
614
Param: unsigned int write_mask
615
Param: unsigned int * bits
616
Description:
617
The function comedi_dio_bitfield() allows multiple channels to
618
be read simultaneously from a digital input or digital I/O device.
619
The parameter write_mask and the value pointed to by bits
620
are interpreted as bit fields, with the least significant bit
621
representing channel 0. For each bit in write_mask that is
622
set to 1, the cooresponding bit in *bits is written to the digital
623
output channel. After writing all the output channels, each
624
channel is read, and the result placed in the approprate bits in
625
*bits. The result of reading an output channel is undefined.
626
It is not possible to access channels greater than 31 using this
627
function.
628
629
Function: comedi_sv_init -- slowly-varying inputs
630
Retval: int
631
Param: comedi_sv_t * sv
632
Param: comedi_t * device
633
Param: unsigned int subdevice
634
Param: unsigned int channel
635
Status: deprecated
636
Description:
637
The function comedi_sv_init() initializes the slow varying Comedi
638
structure sv to use the device device, the analog input subdevice
639
subdevice, and the channel channel. The slow varying Comedi
640
structure is used by comedi_sv_measure() to accurately measure
641
an analog input by averaging over many samples. The default
642
number of samples is 100. This function returns 0 on success,
643
-1 on error.
644
645
Function: comedi_sv_update -- slowly-varying inputs
646
Retval: int
647
Param: comedi_sv_t * sv
648
Status: deprecated
649
Description:
650
The function comedi_sv_update() updates internal parameters of
651
the slowly varying Comedi structure sv.
652
653
Function: comedi_sv_measure -- slowly-varying inputs
654
Retval: int
655
Param: comedi_sv_t * sv
656
Param: double * data
657
Status: deprecated
658
Description:
659
The function comedi_sv_measure() uses the slowly varying Comedi
660
structure sv to measure a slowly varying signal. If sucessful,
661
the result (in physical units) is stored in the location pointed
662
to by data, and the number of samples is returned. On error, -1
663
is returned.
664
665
Function: comedi_get_cmd_src_mask -- streaming input/output capabilities
666
Retval: int
667
Param: comedi_t * device
668
Param: unsigned int subdevice
669
Param: comedi_cmd * command
670
Description:
671
The command capabilities of the subdevice indicated by the parameters
672
device and subdevice are probed, and the results placed in the
673
command structure pointed to by the parameter command. The trigger
674
source elements of the command structure are set to the logical OR
675
value of possible trigger sources. Other elements in the structure
676
are undefined. If sucessful, 0 is returned, otherwise -1.
677
678
Function: comedi_get_cmd_generic_timed -- streaming input/output capabilities
679
Retval: int
680
Param: comedi_t * device
681
Param: unsigned int subdevice
682
Param: comedi_cmd * command
683
Param: unsigned int period_ns
684
Description:
685
The command capabilities of the subdevice indicated by the parameters
686
device and subdevice are probed, and the results placed in the
687
command structure pointed to by the parameter command. The command
688
structure pointed to by the parameter command is modified to be a
689
valid command that can be used as a parameter to comedi_command().
690
The command measures samples at a rate that corresponds to the
691
period period_ns. The rate is adjusted to a rate that the device
692
can handle. If sucessful, 0 is returned, otherwise -1.
693
694
Function: comedi_cancel -- stop streaming input/outpu in progress
695
Retval: int
696
Param: comedi_t * device
697
Param: unsigned int subdevice
698
Description:
699
The function comedi_cancel() can be used to stop a Comedi command
700
previously started by comedi_command() that is still in progress
701
on the subdevice indicated by the parameters device and subdevice.
702
This may not return the subdevice to a ready state, since there may
703
be samples in the buffer that need to be read.
704
705
If sucessful, 0 is returned, otherwise -1.
706
707
Function: comedi_command -- start streaming input/output
708
Retval: int
709
Param: comedi_t * device
710
Param: comedi_cmd * command
711
Description:
712
The function comedi_command() starts streaming input or output. The
713
command structure pointed to by the parameter command specifies the
714
acquisition. For input subdevices, sample values are read using the
715
function read(). For output subdevices, sample vlaues are written
716
using the function write().
717
718
If sucessful, 0 is returned, otherwise -1.
719
720
Function: comedi_command_test -- test streaming input/output configuration
721
Retval: int
722
Param: comedi_t * device
723
Param: comedi_cmd * command
724
Description:
725
The function comedi_command_test() tests the command structure pointed
726
to by the parameter command and returns an integer describing the
727
testing stages that were sucessfully passed. In addition, if elements
728
of the command structure are invalid, they may be modified. Source
729
elements are modified to remove invalid source triggers. Argument
730
elements are adjusted or rounded to the nearest valid value.
731
732
XXX return values.
733
734
Function: comedi_poll -- force updating of streaming buffer
735
Retval: int
736
Param: comedi_t * device
737
Param: unsigned int subdevice
738
Description:
739
The function comedi_poll() is used on a subdevice that has a
740
Comedi command in progress in order to update the streaming buffer.
741
If supported by the driver, all available samples are copied to
742
the streaming buffer. These samples may be pending in DMA buffers
743
or device FIFOs. If sucessful, the number of additional bytes
744
available is returned. If there is an error, -1 is returned.
745
746
Function: comedi_set_max_buffer_size -- streaming buffer size of subdevice
747
Retval: int
748
Param: comedi_t * device
749
Param: unsigned int subdevice
750
Param: unsigned int max_size
751
Description:
752
The function comedi_set_max_buffer_size() changes the maximum
753
allowable size (in bytes) of the streaming buffer for the subdevice
754
specified by device and subdevice. Changing the maximum buffer
755
size requires appropriate privileges. If sucessful, the old buffer
756
size is returned. On error, -1 is returned.
757
758
Function: comedi_get_buffer_contents -- streaming buffer status
759
Retval: int
760
Param: comedi_t * device
761
Param: unsigned int subdevice
762
Description:
763
The function comedi_get_buffer_contents() is used on a subdevice
764
that has a Comedi command in progress. The number of bytes that
765
are available in the streaming buffer is returned. If there is
766
an error, -1 is returned.
767
768
Function: comedi_mark_buffer_read -- streaming buffer status
769
Retval: int
770
Param: comedi_t * device
771
Param: unsigned int subdevice
772
Param: unsigned int num_bytes
773
Description:
774
The function comedi_mark_buffer_read() is used on a subdevice
775
that has a Comedi command in progress. This function can be
776
used to indicate that the next num_bytes bytes in the buffer
777
are no longer needed and may be discarded.
778
If there is an error, -1 is returned.
779
780
Function: comedi_get_buffer_offset -- streaming buffer status
781
Retval: int
782
Param: comedi_t * device
783
Param: unsigned int subdevice
784
Description:
785
The function comedi_get_buffer_offset() is used on a subdevice
786
that has a Comedi command in progress. This function returns
787
the offset in bytes of the read pointer in the streaming buffer.
788
This offset is only useful for memory mapped buffers.
789
If there is an error, -1 is returned.
790
791
Function: comedi_get_timer -- timer information (deprecated)
792
Retval: int
793
Param: comedi_t * device
794
Param: unsigned int subdevice
795
Param: double frequency
796
Param: unsigned int * trigvar
797
Param: double * actual_frequency
798
Status: deprecated
799
Description:
800
The function comedi_get_timer converts the frequency frequency
801
to a number suitable to send to the driver in a comedi_trig
802
structure. This function remains for compatibility with very
803
old versions of Comedi, that converted sampling rates to timer
804
values in the libary. This conversion is now done in the kernel,
805
and every device has the timer type nanosec_timer, indicating
806
that timer values are simply a time specified in nanoseconds.
807
808
Function: comedi_timed_1chan -- streaming input (deprecated)
809
Retval: int
810
Param: comedi_t * device
811
Param: unsigned int subdevice
812
Param: unsigned int channel
813
Param: unsigned int range
814
Param: unsigned int aref
815
Param: double frequency
816
Param: unsigned int num_samples
817
Param: double * data
818
Status: deprecated
819
Description:
820
Not documented.
821
822
Function: comedi_set_global_oor_behavior -- out-of-range behavior
823
Retval: int
824
Param: enum comedi_oor_behavior behavior
825
Status: alpha
826
Description:
827
This function changes the Comedilib out-of-range behavior.
828
This currently affects the behavior of comedi_to_phys() when
829
converting endpoint sample values, that is, sample values
830
equal to 0 or maxdata. If the out-of-range behavior is set to
831
COMEDI_OOR_NAN, endpoint values are converted to NAN. If the
832
out-of-range behavior is set to COMEDI_OOR_NUMBER, the endpoint
833
values are converted similarly to other values.
834
835
The previous out-of-range behavior is returned.
836
837
Function: comedi_apply_calibration -- set calibration from file
838
Retval: int
839
Param: comedi_t *device
840
Param: unsigned int subdevice
841
Param: unsigned int channel
842
Param: unsigned int range
843
Param: unsigned int aref
844
Param: const char *file_path
845
Status: alpha
846
Description:
847
This function sets the calibration of the specified subdevice
848
so that it is in proper calibration when using the specified
849
channel, range and aref. Depending on the hardware, the
850
calibration settings used may or may not depend on the channel,
851
range, or aref. The file_path parameter can be used
852
to specify the file which contains the calibration information.
853
If <parameter>file_path</parameter> is NULL, then comedilib
854
will use a default
855
file location. The calibration information used by this function
856
is generated by the comedi_calibrate program (see its man page).
857
858
The functions comedi_parse_calibration_file(),
859
comedi_apply_parsed_calibration(), and comedi_cleanup_calibration()
860
provide the same functionality at a slightly lower level.
861
Returns:
862
Zero on success, a negative number on failure.
863
864
Function: comedi_apply_parsed_calibration -- set calibration from memory
865
Retval: int
866
Param: comedi_t * device
867
Param: unsigned int subdevice
868
Param: unsigned int channel
869
Param: unsigned int range
870
Param: unsigned int aref
871
Param: const comedi_calibration_t *calibration
872
Status: alpha
873
Description:
874
This function is similar to comedi_apply_calibration()
875
except the calibration information is read from memory
876
instead of a file. This function can be more
877
efficient than comedi_apply_calibration() since the
878
calibration file does not need to be reparsed with
879
every call. The <parameter>calibration</parameter> is
880
obtained by a call to comedi_parse_calibration_file().
881
882
Returns:
883
Zero on success, a negative number on failure.
884
885
Function: comedi_cleanup_calibration_file -- free calibration resources
886
Retval: void
887
Param: comedi_calibration_t *calibration
888
Status: alpha
889
Description:
890
This function frees the resources associated with a
891
<parameter>calibration</parameter> obtained from
892
comedi_parse_calibration_file(). <parameter>calibration</parameter>
893
can not be used again after calling this function.
894
895
Function: comedi_get_default_calibration_path -- get default calibration file path
896
Retval: char*
897
Param: comedi_t *dev
898
Status: alpha
899
Description:
900
This function returns a string containing a default calibration file
901
path appropriate for <parameter>dev</parameter>. Memory for the
902
string is allocated by the function, and should be freed when
903
the string is no longer needed.
904
Returns:
905
A string which contains a file path useable by
906
comedi_parse_calibration_file(). On error, NULL is returned.
907
908
Function: comedi_parse_calibration_file -- set calibration
909
Retval: comedi_calibration_t*
910
Param: const char *file_path
911
Status: alpha
912
Description:
913
This function parses a calibration file (produced by the
914
comedi_calibrate program) and returns a pointer to a
915
comedi_calibration_t which can be passed to the
916
comedi_apply_parsed_calibration() function. When you are
917
finished using the comedi_calibration_t, you should
918
call comedi_cleanup_calibration() to free the resources
919
associated with the comedi_calibration_t.
920
921
The comedi_get_default_calibration_path() function may
922
be useful in conjunction with this function.
923
Returns:
924
A pointer to parsed calibration information on success, or NULL on failure.
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Version: 2.0.1