ENUM(9)

NAME
enum - enumerate integer values into bits

SYNOPSIS

loadrt enum enums=E;enum1pin1;enum1pin2;;;enum1pin3,D;;;enum2pin1;enum2pin2 [names=name1,name2]

DESCRIPTION

enum converts integer values into bits and vice versa.

The component is especially suitable for encoding and decoding register values for modbus devices, where control commands and status are frequently encoded as enumerations rather than bits. For example 0 = stop, 1 = forwards, 2 = backwards, 3 = jog-forwards etc.

The pins created and the behaviour of the component are controlled by the load-time modparams "enums=" and "names="

The enums= parameter should be a comma-separated list of semicolon- separated pin labels. The enumerated values will increase in sequence starting at zero. To skip a value use a zero-length label, ie two consecutive semicolons, as shown in the examples.

There should be no spaces in the "enums=" list.

"names=" is an optional list of component instance names. If "names=" is omitted the functions and pins will be named "enum-decode...." or "enum-encode...."

Taking the example configuration above, if enum-decode.01.enum2pin1-in is set to TRUE then the output pin enum-decode.01.output will be set to the value 2. If enum-decode.01.enum2pin2-in is set to true then the output would be 3.

Conversely, if enum-encode.00.input is set to 4 then the pin enum-encode.00.enum1pin3-out will be set to TRUE.

OPTIONS

Preceding the list of labels should be the control-codes "D" for decode or "E" for encode. A D-type enum will set the value of HAL bit pins in response to changes to the enum-decode.NN.input value, whereas an E-type enum will set the value of the enum-encode.NN.output integer depending on which enum-encode.NN.label-bit value is set.

If more than one label-bit input pin is set the output value will correspond to the pin label later in the list.

E and D-type enumerations may be freely mixed in separate instances.

FUNCTIONS

enum-decode.NN - if instance type = "D"

enum-encode.NN - if instance type = "E"

PINS

enum-decode.NN.input - The integer value to be decoded

enum-decode.NN.label-out - output bits of a decode instance

enum-decode.NN.label-val - The enumeration value corresponding to each specific bit output. These are populated in sequence during loading but may be over-ridden in HAL if convenient.

enum-encode.NN.label-in - input bits of a decode instance

enum-encode.NN.label-val - The enumeration value corresponding to each specified bit input. These are populated in sequence during loading but may be over-ridden in HAL if convenient.

enum-decode.NN.output - The integer value corresponding to the set bit input.

BUGS

If no bits are set the output value will be zero even if zero is a defined enumeration.

AUTHOR

Andy Pugh

REPORTING BUGS

Report bugs to at the LinuxCNC github issues list: https://github.com/LinuxCNC/linuxcnc/issues

COPYRIGHT

Copyright © 2023 Andy Pugh. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.