egd_start(3) [debian man page]

EGD_START(3)						       EEGDEV library manual						      EGD_START(3)

NAME

       egd_start, egd_stop - start and stop buffered acquisition

SYNOPSIS

       #include <eegdev.h>

       int egd_start(struct eegdev* dev);
       int egd_stop(struct eegdev* dev);

DESCRIPTION

       egd_start()  marks the beginning of buffered acquisition from the device referenced by dev. This means that the data starts getting accumu-
       lated in an internal ringbuffer and this buffered data can be sequentially obtained by successive  calls  to  egd_get_data(3).  A  buffered
       acquisition started implies that the user has to get the data often enough to prevent the situation of a full ringbuffer.

       egd_stop() halts the buffered acquisition of the device referenced by dev, relieving the user from the obligation to get data regularly.

RETURN VALUE

       The function returns 0 in case of succes. Otherwise, -1 is returned and errno is set accordingly.

ERRORS

       egd_start() and egd_stop() will fail if:

       EINVAL dev is NULL.

SEE ALSO

       egd_get_data(3), egd_get_available(3)

EPFL
								       2010							      EGD_START(3)

EGD_ACQ_SETUP(3)					       EEGDEV library manual						  EGD_ACQ_SETUP(3)

NAME

       egd_acq_setup - specify which and how channel data should be obtained

SYNOPSIS

       #include <eegdev.h>

       int egd_acq_setup(struct eegdev* dev,
			 unsigned int narr, const size_t *strides,
			 unsigned int ngrp, const struct grpconf *grp);

DESCRIPTION

       egd_acq_setup() configures the way data is provided by the device referenced by dev for the next calls to egd_get_data(3).

       The  narr  argument specifies the number of buffers that will be supplied in the argument list of egd_get_data(3). strides should points to
       an array of narr values specifying respectively for each buffers its stride, i.e. the size in bytes between the data of two successive sam-
       ples in this buffer.

       The  channels  data  that  must	be  returns in those buffers are defined by ngrp groups of consecutive channels. The groups definition are
       passed by grp which points to an array of ngrp structures, defined as follows:

	   struct grpconf {
	       unsigned int sensortype;    /* type of channel */
	       unsigned int index;	   /* index of the first channel */
	       unsigned int nch;	   /* number of channels */
	       unsigned int iarray;	   /* index of the array */
	       unsigned int arr_offset;    /* offset in the array */
	       unsigned int datatype;	   /* type in the array */
	   };

       The different fields in the structure defines the properties of the group:

	* sensortype specifies the type of channel. it must one of the following values returned by egd_sensor_type(3).

	* index indicates the index of the first channel in the group. Note that channel index i refers the i-th channel  of  the  type  specified
	  previously, i.e. the channel index i refers to two differents channels if sensortype differs.

	* nch specifies the number of consecutive channels that should be in the group.

	* iarray indicates which buffer the data of the channel group must be written to.

	* arr_offset defines the offset of the memory location of the data in the buffers relatively to the beginning of each sample.

	* datatype  specifies  the type of data that must be written to the buffer. It must be one of the following value: EGD_INT32, EGD_FLOAT or
	  EGD_DOUBLE

RETURN VALUE

       The function returns 0 in case of succes. Otherwise, -1 is returned and errno is set accordingly.

ERRORS

       egd_acq_setup() will fail if:

       EINVAL dev is NULL.

       EPERM  The acquisition is running

THREAD SAFETY

       egd_acq_setup() is thread-safe.

EXAMPLE

       See egd_get_data(3) for a example

SEE ALSO

       egd_get_data(3), egd_start(3), egd_sensor_type(3)

EPFL
								       2010							  EGD_ACQ_SETUP(3)