-- PWM (Pulse Width Modulated) output services using libsimpleio -- Copyright (C)2017-2023, Philip Munts dba Munts Technologies. -- -- Redistribution and use in source and binary forms, with or without -- modification, are permitted provided that the following conditions are met: -- -- * Redistributions of source code must retain the above copyright notice, -- this list of conditions and the following disclaimer. -- -- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" -- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE -- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE -- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE -- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR -- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF -- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS -- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN -- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) -- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -- POSSIBILITY OF SUCH DAMAGE. -- Beware: Many PWM controllers impose a common PWM pulse frequency on -- all channels. If you attempt to configure different channels on the -- same PWM controller to different frequencies, you may not get correct -- output pulse trains. WITH Device; PACKAGE PWM.libsimpleio IS -- Type definitions TYPE Polarities IS (ActiveLow, ActiveHigh); TYPE OutputSubclass IS NEW PWM.OutputInterface WITH PRIVATE; Destroyed : CONSTANT OutputSubclass; -- PWM output object constructor FUNCTION Create (desg : Device.Designator; frequency : Positive; dutycycle : PWM.DutyCycle := PWM.MinimumDutyCycle; polarity : Polarities := ActiveHigh) RETURN PWM.Output; -- PWM output object initializer PROCEDURE Initialize (Self : IN OUT OutputSubclass; desg : Device.Designator; frequency : Positive; dutycycle : PWM.DutyCycle := PWM.MinimumDutyCycle; polarity : Polarities := ActiveHigh); -- PWM output object destroyer PROCEDURE Destroy(Self : IN OUT OutputSubclass); -- PWM output write methods PROCEDURE Put (Self : IN OUT OutputSubclass; dutycycle : PWM.DutyCycle); PROCEDURE Put (Self : IN OUT OutputSubclass; ontime : Duration); -- Retrieve the configured PWM pulse period FUNCTION GetPeriod(Self : IN OUT OutputSubclass) RETURN Duration; -- Retrieve the underlying Linux file descriptor FUNCTION fd(Self : OutputSubclass) RETURN Integer; PRIVATE -- Check whether PWM output has been destroyed PROCEDURE CheckDestroyed(Self : OutputSubclass); TYPE OutputSubclass IS NEW Standard.PWM.OutputInterface WITH RECORD fd : Integer := -1; period : Duration := 0.0; END RECORD; Destroyed : CONSTANT OutputSubclass := OutputSubclass'(-1, 0.0); END PWM.libsimpleio;