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imET
Joined: 05 Jul 2005
Posts: 4
Location: Canada
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| step and direction output for stepper controller. |
 Posted: Wed Mar 22, 2006 6:55 pm |
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Hi,
I'm trying to build an XY pen plotter and
I'm wondering what is a better way of
sending step pulse to a stepper controller,
I basically just sending steps to a stepper
controller by turning a pin Hi or Lo as you could
see below:
| Code: |
void point2d(SINT32 x, SINT32 y, SINT32 x2, SINT32 y2)
{
/* output the point */
setDirection();
delay_ms(PulseWidth);//delay between steps
if(sx != 0)output_high(STEP_X);
if(sy != 0)output_high(STEP_Y);
delay_ms(PulseWidth);//delay between steps
output_low(STEP_Y);
output_low(STEP_X);
//printf(lcd_putc, "\f%ld %ld", x,y);
//printf(lcd_putc,"\n%d", PulseWidth);
// Pseudo Acceleration/Deceleration,
if ((x - x2) >= MinStep | (y - y2) >= MinStep)
PulseWidth -= 1;
else
PulseWidth += 1;
if(PulseWidth <= MaxPulseWidth) PulseWidth = MaxPulseWidth;
if(PulseWidth >= 50) PulseWidth = 50;
//printf(lcd_putc,"\f%ld", count);
}//end point2d
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kender
Joined: 09 Aug 2004
Posts: 768
Location: Silicon Valley
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| Posted: Wed Mar 22, 2006 9:33 pm |
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| If you haven't done it already, take a look at the CCS' example EX_STEP.C . |
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imET
Joined: 05 Jul 2005
Posts: 4
Location: Canada
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| Posted: Thu Mar 23, 2006 3:27 pm |
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Thanks, but I'm not trying to make a stepper controller,
I already have a stepper controller base on Allegro 3977SED.
I'm basically just sending steps and direction to the controller,
and I think there's a better way, than what was done in the previous posted code is doing.
here's some more of the code if it would helps.
It's part of the code I found online, so I'm not putting a claim to it.,
the original code is designed to do 3 axis, but I only need the two.
| Code: |
void line2D(SINT32 x1, SINT32 y1, SINT32 x2, SINT32 y2)
{
//SINT32 x, y;
SINT32 ax, ay;
SINT32 xd, yd;
SINT32 dx, dy;
//Difference between start and endpoint
dx = x2 - x1;
dy = y2 - y1;
/* TrueDistance:= SQRT(SQR(Xdest - X) + SQR(Ydest - Y));
Pythagorean theroem*/
/*
// absolute value of a
//#define ABS(a) (((a) < 0)? -(a):(a))
ax = ABS(dx) << 1;
ay = ABS(dy) << 1;
//xInc = dx / stepDiv;
//yInc = dy / stepDiv;
//ax = ABS((dx) / stepDiv);// determine how far each axis should move
//ay = ABS((dy) / stepDiv);
// take sign of a, either -1, 0, or 1
//#define ZSGN(a) (((a) < 0)? -1 : (a) >0 ? 1 : 0)
sx = ZSGN(dx);//is dx 1, 0, or -1
sy = ZSGN(dy);//is dy 1, 0, or -1 / 1=CW : 0 or -1 =CCW
x = x1;
y = y1;
//X axis dominant ?
if (ax >= ay )
{
yd = ay - (ax >> 1);
for (;;)
{
point2d(x,y,x2,y2); //X is the driving axis hence dominant
if (x == x2)
{
return; //current move completed
}
if (yd >= 0)
{
y += sy;
yd -= ax;
}
x += sx;
yd += ay;
}//end for
}
//Y axis dominant ?
else if (ay >= ax)
{
xd = ax - (ay >> 1);
for (;;)
{
point2d(x, y,x2,y2);
if (y == y2)
{
return;
}
if (xd >= 0)
{
x += sx;
xd -= ay;
}
y += sy;
xd += ax;
}//end for
}//end elseif
} //end line2d
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