kst_driver_t Struct Reference

The driver: the only way to the wire. More...

#include <kst_session.h>

Data Fields
void *	ctx
bool(*)	start (void *ctx, const kst_frame_t *frame, uint32_t window_ns)
	Clocks out frame and records the line up to window_ns; false when it cannot start.
bool(*)	poll (void *ctx, kst_capture_t *out)
	Reports the window's end: false while the transaction runs; true once, with out filled.
uint32_t(*)	now_us (void *ctx)

Detailed Description

The driver: the only way to the wire.

Contract:

• Outside a transaction the line is low.
• start() clocks out frame->n_half half-cells of KST_HALF_CELL_NS each, taken from kst_frame_level(), drives low for KST_RELEASE_NS, switches to input and records every level change until window_ns after the frame's last edge. It returns at once; false when it cannot start.
• poll() returns false while the transaction runs. When the window has ended it fills out and returns true, once.
• now_us() is a free-running microsecond clock. It may wrap; the session uses differences only.

There is no delay function: the session waits by returning from kst_session_step().

Field Documentation

ctx

void* kst_driver_t::ctx

driver state, passed to each function

now_us

uint32_t(*) kst_driver_t::now_us(void *ctx)

free-running microseconds, may wrap

poll

bool(*) kst_driver_t::poll(void *ctx, kst_capture_t *out)

Reports the window's end: false while the transaction runs; true once, with out filled.

Parameters

ctx	Driver state, as in the struct.
out	Receives the capture when the window has ended.

Returns

true once, after the window has ended; false while it runs.

start

bool(*) kst_driver_t::start(void *ctx, const kst_frame_t *frame, uint32_t window_ns)

Clocks out frame and records the line up to window_ns; false when it cannot start.

Parameters

ctx	Driver state, as in the struct.
frame	Frame to send.
window_ns	Time in ns to record after the frame's last edge.

Returns

false when the call cannot start; true otherwise.

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

• protocols/kst/include/kst_session.h