please dont rip this site
//===================================================================//
//                         SERVOTST.C                                //
//===================================================================//
//	By:		Dale Botkin <dale@botkin.org>					    //
//	Date:	3/15/2000                                             //
//-------------------------------------------------------------------//
// Simple C program for the PIC MPU, pretty much any variety.  Will  //
// exercise up to four R/C servos connected to pins RB0:3.  I tested //
// this with three, but it's pretty obvious you need to power the    //
// servos separately from the PIC to cut down on glitches.  Very     //
// easy to modify for up to 8 servos, though every servo you add     //
// sucks up another 10% of available CPU time.  Since all we're      //
// doing is exercising them, though, using 80% of CPU time running   //
// the pulses is no biggie.                                          //
//-------------------------------------------------------------------//
// Copyright (C)2000, Dale Botkin, all rights reserved.  You may use //
// this code freely for personal, non-commercial use.  In the highly //
// unlikely event that you want to use this code for commercial use, //
// email me to make arrangements.                                    //
//-------------------------------------------------------------------//


#include "16C711.H"					// Change for your CPU
#include "int16CXX.h"

#pragma config WDTE=off, FOSC=XT, BODEN=on
#pragma config |= 0x3FB0  			// Code protect off

char	servo_pin;					// Variable for port pins
char	servo[4];						// Servo position values
char	servo_num;					// Pointer to current servo position value
char	position;						// Working servo position value
char	window;						// 2ms - position value
char	boogies;						// Interrupt counter
char	loops;						// Loop counter
char	current;						// same as servo_num, but outside of interrupt
bit	direction;					// direction of travel flag

#pragma	origin 4

		// With .1ms resolution, we can control the servo in 10% steps:
		// 10 = 0 degrees (or 100% backward motion)		1.0ms
		// 11 = 18 degrees (or 80% backward motion)		1.1ms
		// 12 = 36 degrees (or 60% backward motion)		1.2ms
		// 13 = 54 degrees (or 40% backward motion)		1.3ms
		// 14 = 72 degrees (or 20% backward motion)		1.4ms
		// 15 = 90 degrees (or stopped)				1.5ms
		// 16 = 108 degrees (or 20% forward motion)		1.6ms
		// 17 = 126 degrees (or 40% forward motion)		1.7ms
		// 18 = 144 degrees (or 60% forward motion)		1.8ms
		// 19 = 162 degrees (or 80% forward motion)		1.9ms
		// 20 = 180 degrees (or 100% forward motion)		2.0ms
		// So our pulse routine needs to run 1ms + x tenths.
		// Next version will (maybe) use hundredths, from 100 to 200.

interrupt scan_servos() {
	PORTA = 2;									// indicate where we are
	T0IF = 0;										// Clear TMR0 interrupt flag
	int_save_registers								// Save status & W reg
	char fsr; fsr = FSR;							// Save FSR
	OPTION = 8;									// No TMR0 prescaler
	servo_pin = 1;									// Set up for first servo 
	for(servo_num = 0; servo_num <=3; servo_num++) {
		position = servo[servo_num];					// get pulse width value
		window = 30 - position;						// Figure out remainder of 2ms window
		PORTB = servo_pin;							// Turn on servo pin
	   	TMR0 = 0;									// Clear TMR0
		do {
			TMR0 = 11;							// Adjust for execution time
			while ( TMR0 < 100 );					// wait 100 uS
		} while( --position > 0 );					// for as many as we need
		PORTB = 0;								// Turn off all servo pins
			// Now we have to burn up the remainder of the 2ms total pulse
			// window...
		if(window > 0) {
			do {
					TMR0 = 11;					// Adjust for execution time
				while ( TMR0 < 100 );				// wait 100 uS
			} while(--window > 0);					// for as many as we need
		}
			// And set us up for the next servo in line...
		servo_pin = servo_pin*2;						// Set up for next servo in line
	}
		
		// Now we set up for an 8ms delay until the ext interrupt.
		// We just spent 8ms pulsing the servos, so in another 12 we
		// need to do it again.
	int_restore_registers							// Retrieve the registers
	FSR = fsr;									// Restore FSR
	OPTION = 5;									// 256 prescaler for TMR0
	TMR0 = 187;									// Set up for 12ms interrupt
	boogies++;									// Increment boogie counter
	PORTA = 0;
}
	

void main(){
	T0CS = 0;										// T0 on instruction cycle
	T0SE = 1;										// rising edge
	clearRAM();									// start with clear RAM
	PORTA = 0;						
	PORTB = 0;									// All outputs off
	TRISA = 0;
	TRISB = 0;									// Port B is all output
	OPTION = 5;									// Prescaler set to 256
	direction = 0;										
	
		// Set all servo position registers to the 90 degree mid point.
	for(current = 0; current < 4; current++) {
		servo[current] = 15;
	} 
	TMR0 = 131;									// Set up timer for 8ms
	T0IE = 1;										// Enable TMR0 interrupt
	GIE = 1;										// Duh.

		// The boogie counter gets updated every 20ms, so 50 boogies
		// equals one second.  Tip of the hat to bogomips.

		// First wait 2 seconds to let us see how the servos do at deadband
	while(boogies < 100);							// Loop for 2 seconds

		// Now do 60 loops of 10% steps once a second, full motion
		// range from 10 to 20 and back.  Should take 1 minute.
	direction = 1;
	loops = 0;
	PORTA = 1;
	do {
		boogies = 0;								// clear boogie counter
		while( boogies < 10 );						// Wait 1/5 second	
		for(current=0; current < 4; current++) {
			if(servo[current] == 25) direction = 0;
			if(servo[current] == 5) direction = 1;
			if(direction == 0) servo[current]--;
			if(direction == 1) servo[current]++;
		}
	} while(++loops < 60);

		// Now recenter the servos for 2 seconds 
	for(current=0; current < 4; current++) {
		servo[current] = 15;
	}		
	boogies = 0;
	while(boogies < 100);

		// Now we finish up with 10 full-travel swings, 10 to 20,
		// with a 2-second delay in between. 

	loops = 0;
	PORTA = 0xD;
	do {
		boogies = 0;
		while(boogies < 100);						// 2 second delay
		for(current=0; current < 4; current++) {
			if(servo[current] == 25) direction = 0;
			else if(servo[current] == 5) direction = 1;
			else if(servo[current] > 5 && servo[current] < 25) direction = 0;
			if(direction == 0) servo[current] = 5;
			if(direction == 1) servo[current] = 25;
		}
	} while(++loops < 10);

		// And loop forever.
	main();
}


file: /Techref/microchip/servotst.c.htm, 24KB, , updated: 2000/11/28 14:12, local time: 2024/12/23 06:29,
TOP NEW HELP FIND: 
18.119.116.77:LOG IN

 ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!

<A HREF="http://massmind.org/Techref/microchip/servotst.c.htm"> Colorized Source Code</A>

After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.


Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?

 

Welcome to massmind.org!

 

Welcome to massmind.org!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  .