Intel 8254 Programmable Interrupt Timer (PIT). More...

#include <IntelPIT.h>

Inheritance diagram for IntelPIT:

Public Member Functions
	IntelPIT ()
	Constructor. More...

uint	getCounter ()
	Get current timer counter. More...

virtual Result	setFrequency (Size hertz)
	Set interrupt frequency. More...

Result	waitTrigger ()
	Busy wait for one trigger period. More...

Public Member Functions inherited from Timer
struct Timer::Info	ALIGN (8) Info
	Timer information structure. More...

	Timer ()
	Constructor. More...

Size	getInterrupt () const
	Get timer interrupt number. More...

Size	getFrequency () const
	Get timer frequency. More...

virtual Result	getCurrent (Info *info, const Size msecOffset=0)
	Get current timer info. More...

virtual Result	initialize ()
	Initialize the timer. More...

virtual Result	start ()
	Start the timer. More...

virtual Result	stop ()
	Stop the timer. More...

virtual Result	tick ()
	Process timer tick. More...

virtual Result	wait (u32 microseconds) const
	Busy wait a number of microseconds. More...

bool	isExpired (const Info &info) const
	Check if a timer value is expired. More...

Private Types
enum	Registers { Control = 0x43, Channel0Data = 0x40 }
	Hardware registers. More...

enum	ControlFlags { Channel0 = 0, LatchedRead = 0, AccessLowHigh = (3 << 4), SquareWave = (3 << 1), RateGenerator = (2 << 1) }
	Control Register Flags. More...

Private Member Functions
Result	setControl (ControlFlags flags)
	Set Control register. More...

Private Attributes
IntelIO	m_io
	I/O instance. More...

Static Private Attributes
static const uint	OscillatorFreq = 1193182
	Oscillator frequency in hertz used by the PIT. More...

static const uint	InterruptNumber = 0
	The IRQ vector for channel 0 is fixed to IRQ0. More...

Additional Inherited Members
Public Types inherited from Timer
enum	Result { Success, NotFound, IOError, InvalidFrequency }
	Result codes. More...

Data Fields inherited from Timer
enum Timer::Result	ALIGN

Protected Attributes inherited from Timer
Size	m_ticks
	The current timer ticks. More...

Size	m_frequency
	Frequency of the Timer. More...

Size	m_int
	Timer interrupt number. More...

Detailed Description

Intel 8254 Programmable Interrupt Timer (PIT).

Definition at line 40 of file IntelPIT.h.

Member Enumeration Documentation

◆ ControlFlags

enum IntelPIT::ControlFlags

private

Control Register Flags.

Enumerator
Channel0
LatchedRead
AccessLowHigh
SquareWave
RateGenerator

Definition at line 62 of file IntelPIT.h.

◆ Registers

enum IntelPIT::Registers

private

Hardware registers.

Enumerator
Control
Channel0Data

Definition at line 53 of file IntelPIT.h.

Constructor & Destructor Documentation

◆ IntelPIT()

IntelPIT::IntelPIT ( )

Constructor.

Definition at line 20 of file IntelPIT.cpp.

References InterruptNumber, and Timer::m_int.

Member Function Documentation

◆ getCounter()

uint IntelPIT::getCounter ( )

Get current timer counter.

The timer counter is used internally by the PIT to generate interrupts on the desired frequency. The PIT will decrement the timer counter until 0 is reached, at which it will generate an interrupt and restart at the initial timer counter value.

Returns: Current timer counter.

Definition at line 26 of file IntelPIT.cpp.

References Channel0, Channel0Data, IntelIO::inb(), LatchedRead, m_io, and setControl().

Referenced by waitTrigger().

◆ setControl()

IntelPIT::Result IntelPIT::setControl ( IntelPIT::ControlFlags flags )

private

Set Control register.

Parameters

flags New flags to set in the Control register.

Returns: Result code.

Definition at line 76 of file IntelPIT.cpp.

References Control, flags, m_io, IntelIO::outb(), and Timer::Success.

Referenced by getCounter(), and setFrequency().

◆ setFrequency()

IntelPIT::Result IntelPIT::setFrequency ( Size hertz )

virtual

Set interrupt frequency.

This function configures the PIT to generate interrupts on the given frequency. The new frequency will be applied immediately on the interrupts generated.

Parameters

hertz Number of interrupt triggers per second (in hertz)

Returns: Result code.

Reimplemented from Timer.

Definition at line 37 of file IntelPIT.cpp.

References AccessLowHigh, Channel0, Channel0Data, Timer::InvalidFrequency, Timer::m_frequency, m_io, OscillatorFreq, IntelIO::outb(), RateGenerator, setControl(), and Timer::Success.

Referenced by IntelKernel::IntelKernel().

◆ waitTrigger()

IntelPIT::Result IntelPIT::waitTrigger ( )

Busy wait for one trigger period.

Returns: Result code.

Definition at line 58 of file IntelPIT.cpp.

References getCounter(), and Timer::Success.

Referenced by IntelAPIC::start().

Field Documentation

◆ InterruptNumber

const uint IntelPIT::InterruptNumber = 0

staticprivate

The IRQ vector for channel 0 is fixed to IRQ0.

Definition at line 48 of file IntelPIT.h.

Referenced by IntelPIT().

◆ m_io

IntelIO IntelPIT::m_io

private

I/O instance.

Definition at line 126 of file IntelPIT.h.

Referenced by getCounter(), setControl(), and setFrequency().

◆ OscillatorFreq

const uint IntelPIT::OscillatorFreq = 1193182

staticprivate

Oscillator frequency in hertz used by the PIT.

Definition at line 45 of file IntelPIT.h.

Referenced by setFrequency().

The documentation for this class was generated from the following files:

lib/libarch/intel/IntelPIT.h
lib/libarch/intel/IntelPIT.cpp

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ ControlFlags

◆ Registers

Constructor & Destructor Documentation

◆ IntelPIT()

Member Function Documentation

◆ getCounter()

◆ setControl()

◆ setFrequency()

◆ waitTrigger()

Field Documentation

◆ InterruptNumber

◆ m_io

◆ OscillatorFreq