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Programmable Interval Timer

include/pit.h View source View on GitHub

Functions

Section titled “Functions”

pit_init

Section titled “pit_init”
void pit_init(void)
source

pit_set_divisor

Section titled “pit_set_divisor”
void pit_set_divisor(uint16_t divisor)
source

pit_set_frequency

Section titled “pit_set_frequency”
void pit_set_frequency(freq_hz_t freq_hz)
source

pit_set_interval_ns

Section titled “pit_set_interval_ns”
void pit_set_interval_ns(time_ns_t interval_ns)
source

pit_set_periodic_mode

Section titled “pit_set_periodic_mode”
void pit_set_periodic_mode(uint16_t divisor)
source

pit_set_oneshot_mode

Section titled “pit_set_oneshot_mode”
void pit_set_oneshot_mode(uint16_t divisor)
source

pit_wire_periodic_nmi

Section titled “pit_wire_periodic_nmi”
void pit_wire_periodic_nmi(time_ns_t interval_ns)
source

pit_measure_tsc_freq

Section titled “pit_measure_tsc_freq”
freq_hz_t pit_measure_tsc_freq(void)
source

Macros

Section titled “Macros”

IO ports

PIT_PORT_CHANNEL0

Section titled “PIT_PORT_CHANNEL0”
#define PIT_PORT_CHANNEL0 0x40
source

PIT_PORT_CHANNEL1

Section titled “PIT_PORT_CHANNEL1”
#define PIT_PORT_CHANNEL1 0x41
source

PIT_PORT_CHANNEL2

Section titled “PIT_PORT_CHANNEL2”
#define PIT_PORT_CHANNEL2 0x42
source

PIT_PORT_COMMAND

Section titled “PIT_PORT_COMMAND”
#define PIT_PORT_COMMAND 0x43
source

PIT_PORT_CHANNEL

Section titled “PIT_PORT_CHANNEL”
#define PIT_PORT_CHANNEL(ch)
source
Expansion
#define PIT_PORT_CHANNEL(ch) ((uint16_t) (PIT_PORT_CHANNEL0 + (ch)))

PIT_BASE_FREQUENCY_HZ

Section titled “PIT_BASE_FREQUENCY_HZ”
#define PIT_BASE_FREQUENCY_HZ 1193182ULL
source

PIT Base Frequency (1.193182 MHz)

PIT_FREQUENCY

Section titled “PIT_FREQUENCY”
#define PIT_FREQUENCY 1193182ULL
source

PIT_CMD_CHANNEL

Section titled “PIT_CMD_CHANNEL”
#define PIT_CMD_CHANNEL(ch)
source
Expansion
#define PIT_CMD_CHANNEL(ch) ((uint8_t) (((ch) & 0x3) << 6))

PIT_CMD_CHANNEL0

Section titled “PIT_CMD_CHANNEL0”
#define PIT_CMD_CHANNEL0 0x00
source

PIT_CMD_CHANNEL1

Section titled “PIT_CMD_CHANNEL1”
#define PIT_CMD_CHANNEL1 0x40
source

PIT_CMD_CHANNEL2

Section titled “PIT_CMD_CHANNEL2”
#define PIT_CMD_CHANNEL2 0x80
source

PIT_CMD_READBACK

Section titled “PIT_CMD_READBACK”
#define PIT_CMD_READBACK 0xC0
source

PIT_CMD_ACCESS_LATCH

Section titled “PIT_CMD_ACCESS_LATCH”
#define PIT_CMD_ACCESS_LATCH 0x00
source

Latch count value command

PIT_CMD_ACCESS_LO

Section titled “PIT_CMD_ACCESS_LO”
#define PIT_CMD_ACCESS_LO 0x10
source

Low byte only

PIT_CMD_ACCESS_HI

Section titled “PIT_CMD_ACCESS_HI”
#define PIT_CMD_ACCESS_HI 0x20
source

High byte only

PIT_CMD_ACCESS_LOHI

Section titled “PIT_CMD_ACCESS_LOHI”
#define PIT_CMD_ACCESS_LOHI 0x30
source

Low byte then high byte (16 bit)

Operating Modes

PIT_CMD_MODE_ONESHOT

Section titled “PIT_CMD_MODE_ONESHOT”
#define PIT_CMD_MODE_ONESHOT 0x00
source

PIT_CMD_MODE_HW_ONESHOT

Section titled “PIT_CMD_MODE_HW_ONESHOT”
#define PIT_CMD_MODE_HW_ONESHOT 0x02
source

PIT_CMD_MODE_RATE_GEN

Section titled “PIT_CMD_MODE_RATE_GEN”
#define PIT_CMD_MODE_RATE_GEN 0x04
source

PIT_CMD_MODE_SQUARE_WAVE

Section titled “PIT_CMD_MODE_SQUARE_WAVE”
#define PIT_CMD_MODE_SQUARE_WAVE 0x06
source

PIT_CMD_MODE_SW_STROBE

Section titled “PIT_CMD_MODE_SW_STROBE”
#define PIT_CMD_MODE_SW_STROBE 0x08
source

PIT_CMD_MODE_HW_STROBE

Section titled “PIT_CMD_MODE_HW_STROBE”
#define PIT_CMD_MODE_HW_STROBE 0x0A
source

Binary / BCD

PIT_CMD_BINARY

Section titled “PIT_CMD_BINARY”
#define PIT_CMD_BINARY 0x00
source

PIT_CMD_BCD

Section titled “PIT_CMD_BCD”
#define PIT_CMD_BCD 0x01
source

PIT_DEFAULT_MODE

Section titled “PIT_DEFAULT_MODE”
#define PIT_DEFAULT_MODE 0x34
source

PIT_DEFAULT_COUNT

Section titled “PIT_DEFAULT_COUNT”
#define PIT_DEFAULT_COUNT 0x4AF2
source

PIT_CALIBRATION_MODE

Section titled “PIT_CALIBRATION_MODE”
#define PIT_CALIBRATION_MODE 0x30
source

PIT_CALIBRATION_COUNT

Section titled “PIT_CALIBRATION_COUNT”
#define PIT_CALIBRATION_COUNT UINT16_MAX
source

PIT_DIVISOR_MIN

Section titled “PIT_DIVISOR_MIN”
#define PIT_DIVISOR_MIN 1
source

PIT_DIVISOR_MAX_COUNT

Section titled “PIT_DIVISOR_MAX_COUNT”
#define PIT_DIVISOR_MAX_COUNT UINT16_MAX
source

PIT_DIVISOR_ROLLOVER_VAL

Section titled “PIT_DIVISOR_ROLLOVER_VAL”
#define PIT_DIVISOR_ROLLOVER_VAL 0
source

0 is 65536 in binary mode