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<H2><A NAME="SECTION00522000000000000000">
The D/A Driver</A>
</H2>
<P>
The D/A driver has almost the same structure as the A/D board, except
that it adds an additional function, reset_DA() and replaces the two
run-time functions with one function. The bare minimum device driver
description is shown in what follows:
<P>
<PRE>
#include ``main.h''
int RTiC_init_DA_card(void)
{
/* do all card initialization here and do not forget to
reset the DA card !! */
return(RTIC_SUCCESS); /* or RTIC_ERROR, depending */
}
void RTiC_DA_run(void)
{
/* do all periodic jobs here */
}
int RTiC_stop_DA_card(void)
{
/* do all card ``stopping'' functions here */
return(RTIC_SUCCESS); /* or RTIC_ERROR, depending */
}
void RTIC_reset_DA(void)
{
/* reset the card */
}
</PRE>
<P>
Once again, the first function <TT>RTiC_init_DA_card</TT> is run
immediately after the user releases the ``RUN'' button in <TT>xrtic</TT>
and is used to initialize the D/A board. Similarly, the last function,
<TT>RTiC_stop_DA_card</TT> is run immediately after the user releases
the ``STOP'' button in <TT>xrtic</TT>. In both of these cases, the
functions must return either ``RTIC_ERROR'' or ``RTIC_SUCCESS'',
depending on whether an error was encountered or not, respectively.
<P>
The periodic function <TT>RTiC_stop_DA_card</TT> is run once per
controller cycle and should write out the values stored in the data
pointer (<TT>float *RTiC_control</TT>), for example:
<P><PRE>
for (i=0; i<NUM_CONTROL_OUTPUTS; i++)
OUTW(*(RTiC_control+i),DA_BASE);
</PRE>
<P>
The last function, <TT>RTiC_reset_DA</TT> is used to reset the D/A
boards. It takes no arguments and returns none either.
<P>
<BR><HR>
<ADDRESS>
Michael Barabanov
2001-06-19
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