NAME

Device::Velleman::K8055 - interface with Velleman USB Experiment Board.

SYNOPSIS

use Device::Velleman::K8055;

my $device = Device::Velleman::K8055.new(address => 0);

# Blink alternate LEDs
react {
    whenever Supply.interval(0.5) -> $i {
        if $i %% 2 {
            $device.set-all-digital(0b10101010);
        }
        else {
            $device.set-all-digital(0b01010101);
        }
    }
    whenever signal(SIGINT) {
        $device.close(:reset);
        exit;
    }
}

DESCRIPTION

The Velleman K8055 is an inexpensive PIC based board that allows you to control 8 digital and 2 analogue outputs and read five digital and 2 analog inputs via USB. There are LEDs on the outputs that show the state of the outputs (which is largely how I've tested this.)

I guess it would be useful for experimenting or prototyping but it's rather big (about three times as large as a Raspberry Pi) so you may be rather constrained if you want to use it in a project.

This module has a fairly simple interface - I guess that a higher level abstraction could be provided but I only made it as an experiment and am not quite sure what interface would be best yet.

I've used the k8055 library by Jakob Odersky to do the low-level parts rather than binding libusb directly, but all the information is there is someone else wants to do that.

METHODS

method new

method new(Int :$!address where 0 <= * < 4 = 0, Bool :$debug)

The constructor of the class. This will attempt to open the device, throwing an exception if it is unable. The address parameter can be used if there is more than one board plugged in (the default is 0, the first board present.) The :debug parameter will cause the underlying library to output diagnostic information to STDERR, so you probably want to use it sparingly.

method close

method close(Bool :$reset = False)

This closes the device, freeing up any resources. If the :reset parameter is provided, the outputs will be set to 0 switching off the built in LEDs.

method set-all-digital

method set-all-digital(Int $bitmask where * < 256) returns Bool

This sets all the digital outputs based on the bitmask (in the range 0 - 255,) where each of the eight bits represents a single digital output, with the least significant bit being output 1 (nearest the edge of the board,) and so forth.

method set-digital

method set-digital(Int $channel where * < 8, Bool $v) returns Bool

This sets an individual digital channel, numbered 0 - 7 where 0 is output 1, setting True turns the output on and False off.

method set-all-analog

method set-all-analog(AnalogValue $analog0, AnalogValue $analog1) returns Bool

This sets the analog outputs to a voltage in the range 0-5 volts based on the supplied values in the range 0-255, I'm not sure how accurate it is.

method set-analog

method set-analog(Int $channel where 2 > * => 0, AnalogValue $value) returns Bool

This sets the specified analog channel (0 or 1) to the specified value as described above.

method reset-counter

method reset-counter(Int $counter where 2 > * => 0) returns Bool

The board provides two counters on the first two digital inputs. This resets the specifed counter to 0.

method set-debounce-time

method set-debounce-time(Int $counter where 2 > * => 0, Int $debounce where * < 7450) returns Bool {

This sets the timer for the built in "debounce" of the counters on digital inputs 1 or 2, the debounce time is a value 0..7450 (in milliseconds.)

method get-all-input

method get-all-input(Bool :$quick = False)

This returns a list of the five input values which are:

• digitalbitmask - a five bit integer indicating the state of the five digital inputs.

• analog0 - first analog input

• analog1 - second analog input

• counter0 - first counter

• counter1 - second counter

If the quick parameter is supplied, the values may be those buffered and not reflect the actual state of the inputs.

method get-all-output

method get-all-output()

The board itself doesn't provide a mechanism to get the output values, and this is emulated from the internal cache used by the library. A list of five values is returned:

• digitalBitmask - bitmask value of digital outputs (there are 8 digital outputs)

• analog0 - value of first analog output

• analog1 - value of second analog output

• debounce0 - value of first counter's debounce time [ms]

• debounce1 - value of second counter's debounce time [ms]