dx::usb::isoc::correlation Struct Reference

the bus frame clock's correlation with the timestamp clock, the same in every environment: which frame the tick serves, where the wire is now, when a frame starts More...

#include <dx_usb_isoc.h>

Public Member Functions
int64_t	due (uint64_t frame, int64_t period) const
	the timestamp of a bus frame's start by the plain correlation: the tick's wait target - locked to the phase it would chase its own slop
template<typename source_t>
void	lock (source_t &source, int64_t period)
	the phase exactly: spins to a frame edge, at most a frame - a frozen counter (the bus asleep before the session's first charge) leaves it unset
uint64_t	now (int64_t now, int64_t period) const
	the wire now: the frame under way at now, by the correlation
template<typename source_t>
void	sync (source_t &source, int64_t period, unsigned int ticks)
	the tick's sync: correlates, keeps the phase, picks the objective; ticks the slots of a round
int64_t	timestamp (uint64_t frame, int64_t period) const
	the timestamp of a bus frame's start: by the phase, or by the plain correlation until lock() found one

Public Attributes
int64_t	anchor {}
	the phase: the timestamp of frame 0 - unset until lock() saw a frame edge
struct {
uint64_t   frame
int64_t   timestamp
	the timestamp clock at the frame readout More...
}	correlated
uint64_t	objective {}

Detailed Description

the bus frame clock's correlation with the timestamp clock, the same in every environment: which frame the tick serves, where the wire is now, when a frame starts

The group's tick syncs once per tick: it reads the bus frame counter with its timestamp (correlated), locks the frame clock's phase (anchor: the least timestamp- frame a readout showed, since a readout falls anywhere within its frame - spun to a frame edge once, crept a µs per tick after, following the bus clock's drift) and picks the frame it serves (objective: one per frame - a tick behind by less than a round gets every missed frame in turn, one behind by a round or ahead is resynced). The environment's source supplies os_result readout(uint64_t& frame, int64_t& timestamp) and int64_t now(), the timestamp clock; the bus frame's period comes with every call, in the timestamp clock's units, the round's slots with the sync.

Member Function Documentation

due()

int64_t dx::usb::isoc::correlation::due ( uint64_t frame, int64_t period ) const

inline

the timestamp of a bus frame's start by the plain correlation: the tick's wait target - locked to the phase it would chase its own slop

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lock()

template<typename source_t>

void dx::usb::isoc::correlation::lock ( source_t & source, int64_t period )

inline

the phase exactly: spins to a frame edge, at most a frame - a frozen counter (the bus asleep before the session's first charge) leaves it unset

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now()

uint64_t dx::usb::isoc::correlation::now ( int64_t now, int64_t period ) const

inline

the wire now: the frame under way at now, by the correlation

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sync()

template<typename source_t>

void dx::usb::isoc::correlation::sync ( source_t & source, int64_t period, unsigned int ticks )

inline

the tick's sync: correlates, keeps the phase, picks the objective; ticks the slots of a round

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timestamp()

int64_t dx::usb::isoc::correlation::timestamp ( uint64_t frame, int64_t period ) const

inline

the timestamp of a bus frame's start: by the phase, or by the plain correlation until lock() found one

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Member Data Documentation

anchor

int64_t dx::usb::isoc::correlation::anchor {}

the phase: the timestamp of frame 0 - unset until lock() saw a frame edge

[struct]

struct { ... } dx::usb::isoc::correlation::correlated

frame

uint64_t dx::usb::isoc::correlation::frame

objective

uint64_t dx::usb::isoc::correlation::objective {}

the frame the tick serves

timestamp

int64_t dx::usb::isoc::correlation::timestamp

the timestamp clock at the frame readout

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The documentation for this struct was generated from the following file:

• dx_usb_isoc.h