PIT - Programmable Interval Timer

Overview

The PIT (Programmable Interval Timer) is a hardware timer used in x86 systems to generate interrupts at regular intervals. It plays a key role in OS timekeeping and task scheduling.

In BenOS, the PIT is initialized with a specified frequency to trigger periodic interrupts, which are then handled by the system timer.

Constants

These values are typically used to configure the PIT: - Command port: 0x43
- Channel 0 data port: 0x40
- Default frequency: 1193180 Hz (hardware constant of the PIT)

Functions

void pit_init(uint64_t frequency);

Initializes the PIT to the specified frequency (in Hz).
It computes the divisor from the base frequency (1193180 Hz), then sends the configuration and divisor to the PIT.

Example

pit_init(100); // Initializes the PIT to 100 Hz (every 10ms)