.TH WEIGHTED_SUM "9" "2007-01-16" "LinuxCNC Documentation" "HAL Component"
.SH NAME
weighted_sum \- convert a group of bits to an integer
.SH SYNOPSIS
.B loadrt weighted_sum wsum_sizes=\fIsize[,size,...]\fR
.P
Creates weighted sum groups each with the given number of input bits
(\fIsize\fR).
.SH DESCRIPTION
The weighted_sum converts a group of bits to an integer. The conversion is 
the sum of the weights of the bits that are on plus any offset. The weight 
of the m-th bit is 2^m. This is similar to a binary coded decimal but with 
more options. The hold bit stops processing the input changes so the sum will 
not change.

The default value for each weight is 2^m where m is the bit number. This 
results in a binary to unsigned conversion.

There is a limit of 8 weighted summers and each may have up to 16 input bits.
.SH FUNCTIONS
.TP
.B process_wsums (requires a floating point thread)
Read all input values and update all output values.
.SH PINS
.TP
.B wsum.\fIN\fB.bit.\fIM\fB.in\fR bit in 
The \fIm\fR'th input of weighted summer \fIn\fR.
.TP
.B wsum.\fIN\fB.hold\fR bit in
When TRUE, the \fIsum\fR output does not change.  When FALSE, the \fIsum\fR
output tracks the \fIbit\fR inputs according to the weights and offset.
.TP
.B wsum.\fIN\fB.sum\fR signed out
The output of the weighted summer
.TP
.B wsum.\fIN\fB.bit.\fIM\fB.weight\fR signed rw
The weight of the \fIm\fR'th input of weighted summer \fIn\fR.
The default value is 2^\fIm\fR.
.TP
.B wsum.\fIN\fB.offset\fR signed rw
The offset is added to the weights corresponding to all TRUE inputs to give the
final sum.

.SH SEE ALSO
\fBscaled_s32_sums\fR(9),
\fBsum2\fR(9).