PICnc controller, yeah, its another one...

[The7thGuest]

I heard about PIC-Step and I decided to try my hand at designing my own stepper controller. At the minute I am just working on the step sequence etc... and an algorithm that will allow me to compute 1, 1/2, 1/4, 1/8 etc step modes without the need for a large step table, I just thought I would share my progress so far. If anyone has any input I'd be more than happy to listen to it.

Also, I was considering using TIP-121 NPN Darlington transistors with a max Ic of 6A as my motors run at around 3A each @ 12v so there would be loads or leeway there...

All code is written for a 16F684 and is written in Hi-Tech C Lite.

StepperController.c

/*
// LEGAL JIBBER JABBER	----------------------------------------------------------------

	PICNC FIRMWARE - PIC STEPPER MOTOR CONTROLLER
	Copyright (C) 2007 STEVEN MOUGHAN <STEVEN@THEOBSOLETE.COM>

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

// WIRING CONNECTIONS	----------------------------------------------------------------

OUTPUTS
RA0		A1
RA1		B1
RA2		A2
RA3		B2
RA4		ERROR STATE (E-STOP)
RA5		OPERATIONAL (LIVE)

INPUTS
RC0		STEP MODE, 0 == FULL, 1 == HALF
RC1		ENABLE
RC2		DIRECTION (1 == FORWARDS)
RC3		STEP
RC4		RESET
RC5		E-STOP

*/

#include <pic.h>							//STANDARD PIC HEADER FOR DEFINITIONS
#include "stepfunctions.h"					//CUSTOM FUNCTIONS FOR STEPPER CONTROL

// CUSTOM DEFINITIONS	-----------------------------------------------------------------
#define _STEP_DELAY 1

#define _MODE RC1
#define _ENABLE RC1
#define _DIRECTION RC2
#define _STEP RC3
#define _RESET RC4
#define _ESTOP RC5

#define _A1 RA0
#define _B1 RA1
#define _A2 RA2
#define _B2 RA3

#define _ERROR RA4
#define _OPERATIONAL RA5


//         1       2        3        4          5         6         7         8
__CONFIG(INTIO & WDTDIS & PWRTEN & MCLRDIS & UNPROTECT & BORDIS & IESODIS & FCMDIS);

//	1:	INTERNAL OSC
//	2:	DISABLE WATCH DOG TIMER
//	3:	70mS TIME UP DELAY
// 	4:	DISABLE MCLR
//	5:	DISABLE CODE PROTECTION
//	6:	BROWN OUT DETECT DISABLED
//	7:	INTERNAL EXTERNAL SWITCHOVER MODE DISABLED
//	8:	FAIL-SAFE CLOCK

//	VARIABLE DECLERATIONS	--------------------------------------------------------------


//	FUNCTIONS	--------------------------------------------------------------------------
void step_forwards(void) {
	if(!_MODE) {
		fullstep_forwards();
	} else {
		halfstep_forwards();
	}
	delayMS(_STEP_DELAY);
}	

void step_backwards(void) {
	if(!_MODE) {
		fullstep_backwards();
	} else {
		halfstep_backwards();
	}
	delayMS(_STEP_DELAY);
}

void idle(void) {							//THIS WILL STOP THE PIC
	_ERROR = 1;								//SET ERROR LED
	//_OPERATIONAL = 0;						//CLEAR OPERATIONAL LED
	while(1 == 1) {							//IN CASE OF EMERGENCY
		if(_RESET) {						//CHECK FOR RESET
			_ERROR = 0;						//CLEAR ERROR LED
			//_OPERATIONAL = 1;				//SET OPERATIONAL LED
			return;							//RETURN TO MAIN
		} //END IF
	} //END WHILE
} //END IDLE

void main(void) {
	CMCON0 = 7; 							//TURN OFF COMPARATORS
	ANSEL = 0; 								//TURN OFF ADC
	PORTA = 0x01;		 					//INITIALISE PORTA TO 0x01
	PORTC = 0x00;							//INITIALISE PORTC TO 0x00
	TRISA = 0b000000;						//MAKE PORTA OUTPUT
	TRISC = 0b111111;						//MAKE PORTC INPUT

	//_OPERATIONAL = 1;						//SET OPERATIONAL LED

	while(1 == 1) {							//MAIN PROGRAM LOOP
		if(RC5 == 1) {						//IS ESTOP ACTIVATED
			idle();							//IDLE UNTIL RESET
		}

		if(_STEP && _ENABLE) {
			if(!_DIRECTION) {
				step_backwards();
			} else {
				step_forwards();
			}
		}

	} //END INFINATE LOOP
} //END MAIN

stepfunctions.h

/*
// LEGAL JIBBER JABBER	----------------------------------------------------------------

	PICNC FIRMWARE - PIC STEPPER MOTOR CONTROLLER
	Copyright (C) 2007 STEVEN MOUGHAN <STEVEN@THEOBSOLETE.COM>

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

int x,i,j;									//VARIABLES FOR TIMERS

void delayMS(int time) {					//CREATE A DELAY LASTING 'TIME' NUMBER OF mS
	for(x=0;x<=time;x++) {					//THIS LOOP SHOULD TAKE A TOTAL OF 1uS
		for(i=0;i<=1;i++);					//AND THESE LOOPS CONTROL IT
		for(j=0;j<=60;j++);
	} //END PERMUTATIONS LOOP
} //END DELAYMS	- THIS IS FOR INTERNAL OSC AT 8MHz, IT PROVIDES 1.002mS DELAY PER LOOP

void fullstep_forwards(void) {
	switch(PORTA) {	//  2121
		case(8):
			PORTA = 0b0001;
			break;
		default:
			PORTA = PORTA * 2;
			break;
	}
}

void halfstep_forwards(void) {
	switch(PORTA) {
		case(9):
			PORTA = 0b0001;
			break;
		default:
			PORTA++;
			break;
	}
}

void fullstep_backwards(void) {
	switch(PORTA) {
		case(1):
			PORTA = 0b1000;
			break;
		default:
			PORTA = PORTA / 2;
			break;
	}
}

void halfstep_backwards(void) {
	switch(PORTA) {
		case(1):
			PORTA = 0b1001;
			break;
		default:
			PORTA--;
			break;
	}
}

[niclatrique]

As I see, you haven't implemented the microstep mode yet.

Your program is easy to read that's nice. I'd be interested in your microstepping code once you've programmed it. Let us know.

Thanks a lot for sharing your work

Nic

[Ryobiguy]

Interesting...
It's weird to have code and data in your .h files.

Something you might want to do is to read some timer/counter and keep track of how much time expires instead of getting the CPU stuck in an idle delay loop. It's also trivial to implement debouncing of the step signal.

Something like this maybe should do the trick:

int stepDebounce, lastStep, thisStep;
thisStep = _STEP;
if (stepDebounce) {

// Read timer (if you already havn't on this loop through.)
// Set stepDebounce to zero once enough time has elapsed.

} else if (_ENABLE && thisStep && !lastStep) {

// We just detected a rising edge on step, and enable is on.
stepDebounce = 1; // elapsed time counter and/or just a boolean.
// Enable step pin(s) output

}
lastStep = thisStep;

[The7thGuest]

/*
// LEGAL JIBBER JABBER	----------------------------------------------------------------

	PICNC FIRMWARE - PIC STEPPER MOTOR CONTROLLER
	Copyright (C) 2007 STEVEN MOUGHAN <STEVEN@THEOBSOLETE.COM>

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

// WIRING CONNECTIONS	----------------------------------------------------------------

OUTPUTS
RA0		A1
RA1		B1
RA2		A2
RA3		B2
RA4		ERROR STATE (E-STOP)
RA5		OPERATIONAL (LIVE)

INPUTS
RC0		STEP MODE, 0 == FULL, 1 == HALF
RC1		ENABLE
RC2		DIRECTION (1 == FORWARDS)
RC3		STEP
RC4		RESET
RC5		E-STOP

*/

#include <pic.h>							//STANDARD PIC HEADER FOR DEFINITIONS
#include "stepfunctions.h"					//CUSTOM FUNCTIONS FOR STEPPER CONTROL

// CUSTOM DEFINITIONS	-----------------------------------------------------------------
#define _STEP_DELAY 1

#define _MODE RC1
#define _ENABLE RC1
#define _DIRECTION RC2
#define _STEP RC3
#define _RESET RC4
#define _ESTOP RC5

#define _A1 RA0
#define _B1 RA1
#define _A2 RA2
#define _B2 RA3

#define _ERROR RA4
#define _OPERATIONAL RA5


//         1       2        3        4          5         6         7         8
__CONFIG(INTIO & WDTDIS & PWRTEN & MCLRDIS & UNPROTECT & BORDIS & IESODIS & FCMDIS);

//	1:	INTERNAL OSC
//	2:	DISABLE WATCH DOG TIMER
//	3:	70mS TIME UP DELAY
// 	4:	DISABLE MCLR
//	5:	DISABLE CODE PROTECTION
//	6:	BROWN OUT DETECT DISABLED
//	7:	INTERNAL EXTERNAL SWITCHOVER MODE DISABLED
//	8:	FAIL-SAFE CLOCK

//	VARIABLE DECLERATIONS	--------------------------------------------------------------
int stepDebounce, thisStep, lastStep;

//	CONSTANT DECLERATIONS	--------------------------------------------------------------
const int Twentyms = 1150;				//DECLARE A CONSTANT FOR 20mS DELAY

//	FUNCTIONS	--------------------------------------------------------------------------
void step_forwards(void) {
	if(!_MODE) {
		fullstep_forwards();
	} else {
		halfstep_forwards();
	}
	delayMS(_STEP_DELAY);
}	

void step_backwards(void) {
	if(!_MODE) {
		fullstep_backwards();
	} else {
		halfstep_backwards();
	}
	delayMS(_STEP_DELAY);
}

void idle(void) {							//THIS WILL STOP THE PIC
	_ERROR = 1;								//SET ERROR LED
	//_OPERATIONAL = 0;						//CLEAR OPERATIONAL LED
	while(1 == 1) {							//IN CASE OF EMERGENCY
		if(_RESET) {						//CHECK FOR RESET
			_ERROR = 0;						//CLEAR ERROR LED
			//_OPERATIONAL = 1;				//SET OPERATIONAL LED
			return;							//RETURN TO MAIN
		} //END IF
	} //END WHILE
} //END IDLE

void main(void) {
	CMCON0 = 7; 							//TURN OFF COMPARATORS
	ANSEL = 0; 								//TURN OFF ADC
	PORTA = 0x01;		 					//INITIALISE PORTA TO 0x01
	PORTC = 0x00;							//INITIALISE PORTC TO 0x00
	TRISA = 0b000000;						//MAKE PORTA OUTPUT
	TRISC = 0b111111;						//MAKE PORTC INPUT

	//_OPERATIONAL = 1;						//SET OPERATIONAL LED

	while(1 == 1) {							//MAIN PROGRAM LOOP
		if(_ESTOP == 1) {						//IS ESTOP ACTIVATED
			idle();							//IDLE UNTIL RESET
		}

		thisStep = _STEP;
		if(!stepDebounce) {
			delayMS(20);
			stepDebounce = 1;				//SET
		} else if(_ENABLE && thisStep && !lastStep) {
			stepDebounce = 0;				//RESET
				if(!_DIRECTION) {
					step_backwards();
				} else {
					step_forwards();
				}//END IF
		}//END ELSE IF
		lastStep=thisStep;

	} //END INFINATE LOOP
} //END MAIN

Hows about this? Not sure if I have it 100%, but it does compile. I haven't sim'd yet...

[The7thGuest]

I have created a Source Forge project for the controller. It is available here and the project website is available here.