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Updated the dio function reference

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This commit is contained in:
Frank Mori Hess 2008-02-12 19:31:26 +00:00
parent 0695475797
commit 7eb7a64566
1 changed files with 44 additions and 20 deletions
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64
doc/dio_funcref.txt
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@ -22,9 +22,9 @@ Description:
reading an output channel is the last
value written to the output channel.
All the channels may not be read or written at the exact same time.
All the channels might not be read or written at the exact same time.
For example, the driver may need to sequentially write to
several ports in order to set all the digital channels specified
several registers in order to set all the digital channels specified
by the <parameter>write_mask</parameter>.
Function: comedi_dio_config -- change input/output properties of channel
@ -36,15 +36,16 @@ Param: unsigned int direction
Description:
The function comedi_dio_config() configures individual channels
in a digital I/O subdevice to be either input or output, depending
on the value of parameter direction. Valid directions are
on the value of <parameter>direction</parameter>. Valid directions are
COMEDI_INPUT or COMEDI_OUTPUT.
Depending on the capabilities of the hardware device, multiple
channels may be grouped together to determine direction. In this
Depending on the characteristics of the hardware device, multiple
channels might be grouped together in hardware when
configuring the input/output direction. In this
case, a single call to comedi_dio_config() for any channel in the
group will affect the entire group.
If successful, 1 is returned, otherwise -1.
Returns:
If successful, 0 is returned, otherwise -1.
Function: comedi_dio_get_config -- query input/output properties of channel
Retval: int
@ -53,12 +54,13 @@ Param: unsigned int subdevice
Param: unsigned int channel
Param: unsigned int * direction
Description:
The function comedi_dio_get_config() querys the configuration of
The function comedi_dio_get_config() querys the input/output configuration of
an individual channel
in a digital I/O subdevice (see comedi_dio_config()).
On success, the variable specified by the "direction" pointer will
in a digital I/O subdevice (see
<link linkend="func-ref-comedi-dio-config"><function>comedi_dio_config</function></link>).
On success, *<parameter>direction</parameter> will
be set to either COMEDI_INPUT or COMEDI_OUTPUT.
Returns:
If successful, 0 is returned, otherwise -1.
Function: comedi_dio_read -- read single bit from digital channel
@ -68,14 +70,25 @@ Param: unsigned int subdevice
Param: unsigned int channel
Param: unsigned int * bit
Description:
The function reads the channel channel belonging to the
subdevice subdevice of device device. The data value that is
read is stored in the location pointed to by bit. This function
is equivalent to comedi_data_read(device,subdevice,channel,0,0,bit).
The function comedi_dio_read reads the channel <parameter>channel</parameter>
belonging to the
subdevice <parameter>subdevice</parameter> of device <parameter>device</parameter>.
The data value that is
read is stored in the *<parameter>bit</parameter>. This function
is equivalent to:
<programlisting>
<link linkend="func-ref-comedi-data-read">comedi_data_read</link>(device, subdevice, channel, 0, 0, bit);
</programlisting>
This function does not require a digital subdevice or a subdevice
with a maximum data value of 1 to work properly.
Return values and errors are the same as comedi_data_read().
If you wish to read multiple digital channels at once, it is more efficient to
use
<link linkend="func-ref-comedi-dio-bitfield2"><function>comedi_dio_bitfield2</function></link>
than to call this function multiple times.
Returns:
Return values and errors are the same as
<link linkend="func-ref-comedi-data-read"><function>comedi_data_read</function></link>.
Function: comedi_dio_write -- write single bit to digital channel
Retval: int
@ -84,10 +97,21 @@ Param: unsigned int subdevice
Param: unsigned int channel
Param: unsigned int bit
Description:
The function writes the value bit to the channel channel belonging
to the subdevice subdevice of device device. This function
is equivalent to comedi_data_write(device,subdevice,channel,0,0,bit).
The function writes the value <parameter>bit</parameter> to the channel
<parameter>channel</parameter> belonging
to the subdevice <parameter>subdevice</parameter> of device
<parameter>device</parameter>. This function
is equivalent to:
<programlisting>
comedi_data_write(device, subdevice, channel, 0, 0, bit);
</programlisting>
This function does not require a digital subdevice or a subdevice
with a maximum data value of 1 to work properly.
Return values and errors are the same as comedi_data_write().
If you wish to write multiple digital channels at once, it is more efficient to
use
<link linkend="func-ref-comedi-dio-bitfield2"><function>comedi_dio_bitfield2</function></link>
than to call this function multiple times.
Returns:
Return values and errors are the same as
<link linkend="func-ref-comedi-data-write"><function>comedi_data_write</function></link>.