Module pit

The Programmable Interval Timer (PIT) chip (Intel 8253/8254) basically consists of an oscillator, a prescaler and 3 independent frequency dividers. Each frequency divider has an output, which is used to allow the timer to control external circuitry (for example, IRQ 0).

Reference: https://wiki.osdev.org/Programmable_Interval_Timer

Enums

AccessMode 🔒

This bits tell the PIT what access mode is used for the selected channel.

Channel 🔒

Used to select the configured channel in the MODE_COMMAND_PORT of the PIT.

OperatingMode

PIT Operating Mode.

Constants

TIMER_INTERRUPT 🔒

TIMER_RATE 🔒

Statics

CHANNEL0_PORT 🔒

The output from PIT channel 0 is connected to the PIC chip and generate “IRQ 0”. If connected to PIC, the IRQ0 will generate by the rising edge of the output voltage.

CHANNEL1_PORT 🔒

The output from PIT channel 1 was once used for refreshing the DRAM or RAM so that the capacitors don’t forget their state.

CHANNEL2_PORT 🔒

The output from PIT channel 2 is connected to the PC speaker, so the frequency of the output determines the frequency of the sound produced by the speaker. For more information, check https://wiki.osdev.org/PC_Speaker.

MODE_COMMAND_PORT 🔒

PIT command port.

Functions

enable_interrupt 🔒

Enables the interrupt line that is connected to the PIT.

init 🔒