StuBS
LAPIC::Timer Namespace Reference

Local Timer (for each LAPIC / CPU) More...

Classes

struct  ControlRegister.__unnamed45__
 

Enumerations

enum  DeliveryStatus {
  IDLE = 0 ,
  SEND_PENDING = 1
}
 Timer Delivery Status.
 
enum  TimerMode {
  ONE_SHOT = 0 ,
  PERIODIC = 1 ,
  DEADLINE = 2
}
 Timer Mode.
 
enum  Mask {
  NOT_MASKED = 0 ,
  MASKED = 1
}
 Timer Mask.
 

Functions

uint32_t ticks (void)
 Determines the LAPIC timer frequency. More...
 
void set (uint32_t counter, uint8_t divide, uint8_t vector, bool periodic, bool masked=false)
 Set the LAPIC timer. More...
 
Register getClockDiv (uint8_t div)
 Calculate the bit mask for the LAPIC-timer divider. More...
 

Detailed Description

Local Timer (for each LAPIC / CPU)

See also
ISDMv3 10.5.4 APIC Timer

Class Documentation

◆ LAPIC::Timer::ControlRegister.__unnamed45__

struct LAPIC::Timer::ControlRegister.__unnamed45__
Class Members
uint32_t vector: 8 Vector.
uint32_t __pad0__: 4
DeliveryStatus delivery_status: 1 Delivery Status.
uint32_t __pad1__: 3
Mask masked: 1 Interrupt Mask (if set, interrupt will not trigger)
TimerMode timer_mode: 2 Timer Mode.
uint32_t __pad2__: 13

Function Documentation

◆ ticks()

uint32_t LAPIC::Timer::ticks ( void  )

Determines the LAPIC timer frequency.

This function will calculate the number of LAPIC-timer ticks passing in the course of one millisecond. To do so, this function will rely on PIT timer functionality and measure the tick delta between start and end of waiting for a predefined period.

For measurement, the LAPIC-timer single-shot mode (without interrupts) is used; after measurement, the timer is disabled again.

Note
The timer is counting towards zero.
Returns
Number of LAPIC-timer ticks per millisecond

◆ set()

void LAPIC::Timer::set ( uint32_t  counter,
uint8_t  divide,
uint8_t  vector,
bool  periodic,
bool  masked = false 
)

Set the LAPIC timer.

Parameters
counterInitial counter value; decremented on every LAPIC timer tick
divideDivider (power of 2, i.e., 1 2 4 8 16 32...) used as prescaler between bus frequency and LAPIC timer frequency: LAPIC timer frequency = divide * bus frequency. divide is a numerical parameter, the conversion to the corresponding bit mask is done internally by calling getClockDiv().
vectorInterrupt vector number to be triggered on counter expiry
periodicIf set, the interrupt will be issued periodically
maskedIf set, interrupts on counter expiry are suppressed

◆ getClockDiv()

Register LAPIC::Timer::getClockDiv ( uint8_t  div)

Calculate the bit mask for the LAPIC-timer divider.

Parameters
divDivider, must be power of two: 1, 2, 4, 8, 16, 32, 64, 128
Returns
Bit mask for LAPIC::setTimer() or 0xff if div is invalid.