enum
{
/* The PIT channel value ports. You can write to and read from them.
Do not mess with timer 0 or 1. */
GRUB_PIT_COUNTER_0 = 0x40,
GRUB_PIT_COUNTER_1 = 0x41,
GRUB_PIT_COUNTER_2 = 0x42,
/* The PIT control port. You can only write to it. Do not mess with
timer 0 or 1. */
GRUB_PIT_CTRL = 0x43,
/* The speaker port. */
GRUB_PIT_SPEAKER_PORT = 0x61,
};
/* The speaker port. */
enum
{
/* If 0, follow state of SPEAKER_DATA bit, otherwise enable output
from timer 2. */
GRUB_PIT_SPK_TMR2 = 0x01,
/* If SPEAKER_TMR2 is not set, this provides direct input into the
speaker. Otherwise, this enables or disables the output from the
timer. */
GRUB_PIT_SPK_DATA = 0x02,
GRUB_PIT_SPK_TMR2_LATCH = 0x20
};
/* The PIT control port. You can only write to it. Do not mess with
timer 0 or 1. */