dda_queue.c File Reference

DDA Queue - manage the move queue. More...

#include "dda_queue.h"
#include <string.h>
#include <avr/interrupt.h>
#include "config.h"
#include "timer.h"
#include "serial.h"
#include "sermsg.h"
#include "delay.h"
#include <stdint.h>
#include <util/delay_basic.h>
#include "watchdog.h"
#include "sersendf.h"
#include "clock.h"
#include "memory_barrier.h"

Functions
DDA movebuffer[MOVEBUFFER_SIZE]	__attribute__ ((__section__(".bss")))
	move buffer.
uint8_t	queue_full ()
	check if the queue is completely full
uint8_t	queue_empty ()
	check if the queue is completely empty
void	queue_step ()
	Take a step or go to the next move.
void	enqueue (TARGET *t)
	add a move to the movebuffer
void	enqueue_home (TARGET *t, uint8_t endstop_check, uint8_t endstop_stop_cond)
void	next_move ()
	go to the next move.
void	print_queue ()
	DEBUG - print queue.
void	queue_flush ()
	dump queue for emergency stop.
void	queue_wait ()
	wait for queue to empty
Variables
uint8_t	mb_head = 0
	movebuffer head pointer.
uint8_t	mb_tail = 0
	movebuffer tail pointer.

Detailed Description

DDA Queue - manage the move queue.

Function Documentation

DDA movebuffer [MOVEBUFFER_SIZE] __attribute__ ( (__section__(".bss")) )

move buffer.

holds move queue contents are read/written both in and out of interrupts, but once writing starts in interrupts on a specific slot, the slot will only be modified in interrupts until the slot is is no longer live. The size does not need to be a power of 2 anymore!

void enqueue ( TARGET * t )

add a move to the movebuffer

Note:: this function waits for space to be available if necessary, check queue_full() first if waiting is a problem This is the only function that modifies mb_head and it always called from outside an interrupt.

Referenced by process_gcode_command().

void next_move ( void )

go to the next move.

be aware that this is sometimes called from interrupt context, sometimes not. Note that if it is called from outside an interrupt it must not/can not by be interrupted such that it can be re-entered from within an interrupt. The timer interrupt MUST be disabled on entry. This is ensured because the timer was disabled at the start of the ISR or else because the current move buffer was dead in the non-interrupt case (which indicates that the timer interrupt is disabled).

Referenced by queue_step().

void print_queue ( void )

DEBUG - print queue.

Qt/hs format, t is tail, h is head, s is F/full, E/empty or neither

Referenced by clock_250ms(), and process_gcode_command().

void queue_flush ( void )

dump queue for emergency stop.