RaspberryIO/Unosquare.RaspberryIO/Native/Timing.cs

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2019-02-17 14:08:57 +01:00
namespace Unosquare.RaspberryIO.Native
{
using Swan;
using Swan.Abstractions;
using System;
/// <summary>
/// Provides access to timing and threading properties and methods
/// </summary>
public class Timing : SingletonBase<Timing>
{
/// <summary>
/// Prevents a default instance of the <see cref="Timing"/> class from being created.
/// </summary>
/// <exception cref="NotSupportedException">Could not initialize the GPIO controller</exception>
private Timing()
{
// placeholder
}
/// <summary>
/// This returns a number representing the number of milliseconds since your program
/// initialized the GPIO controller.
/// It returns an unsigned 32-bit number which wraps after 49 days.
/// </summary>
/// <value>
/// The milliseconds since setup.
/// </value>
public uint MillisecondsSinceSetup => WiringPi.Millis();
/// <summary>
/// This returns a number representing the number of microseconds since your
/// program initialized the GPIO controller
/// It returns an unsigned 32-bit number which wraps after approximately 71 minutes.
/// </summary>
/// <value>
/// The microseconds since setup.
/// </value>
public uint MicrosecondsSinceSetup => WiringPi.Micros();
/// <summary>
/// This causes program execution to pause for at least howLong milliseconds.
/// Due to the multi-tasking nature of Linux it could be longer.
/// Note that the maximum delay is an unsigned 32-bit integer or approximately 49 days.
/// </summary>
/// <param name="value">The value.</param>
public static void SleepMilliseconds(uint value) => WiringPi.Delay(value);
/// <summary>
/// This causes program execution to pause for at least howLong microseconds.
/// Due to the multi-tasking nature of Linux it could be longer.
/// Note that the maximum delay is an unsigned 32-bit integer microseconds or approximately 71 minutes.
/// Delays under 100 microseconds are timed using a hard-coded loop continually polling the system time,
/// Delays over 100 microseconds are done using the system nanosleep() function
/// You may need to consider the implications of very short delays on the overall performance of the system,
/// especially if using threads.
/// </summary>
/// <param name="value">The value.</param>
public void SleepMicroseconds(uint value) => WiringPi.DelayMicroseconds(value);
/// <summary>
/// This attempts to shift your program (or thread in a multi-threaded program) to a higher priority and
/// enables a real-time scheduling. The priority parameter should be from 0 (the default) to 99 (the maximum).
/// This wont make your program go any faster, but it will give it a bigger slice of time when other programs
/// are running. The priority parameter works relative to others so you can make one program priority 1 and
/// another priority 2 and it will have the same effect as setting one to 10 and the other to 90
/// (as long as no other programs are running with elevated priorities)
/// </summary>
/// <param name="priority">The priority.</param>
public void SetThreadPriority(int priority)
{
priority = priority.Clamp(0, 99);
var result = WiringPi.PiHiPri(priority);
if (result < 0) HardwareException.Throw(nameof(Timing), nameof(SetThreadPriority));
}
/// <summary>
/// This is really nothing more than a simplified interface to the Posix threads mechanism that Linux supports.
/// See the manual pages on Posix threads (man pthread) if you need more control over them.
/// </summary>
/// <param name="worker">The worker.</param>
/// <exception cref="ArgumentNullException">worker</exception>
public void CreateThread(ThreadWorker worker)
{
if (worker == null)
throw new ArgumentNullException(nameof(worker));
var result = WiringPi.PiThreadCreate(worker);
if (result != 0) HardwareException.Throw(nameof(Timing), nameof(CreateThread));
}
/// <summary>
/// These allow you to synchronize variable updates from your main program to any threads running in your program.
/// keyNum is a number from 0 to 3 and represents a “key”. When another process tries to lock the same key,
/// it will be stalled until the first process has unlocked the same key.
/// </summary>
/// <param name="key">The key.</param>
public void Lock(ThreadLockKey key) => WiringPi.PiLock((int)key);
/// <summary>
/// These allow you to synchronize variable updates from your main program to any threads running in your program.
/// keyNum is a number from 0 to 3 and represents a “key”. When another process tries to lock the same key,
/// it will be stalled until the first process has unlocked the same key.
/// </summary>
/// <param name="key">The key.</param>
public void Unlock(ThreadLockKey key) => WiringPi.PiUnlock((int)key);
}
}