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--- en:examples:motors:stepper [2009/09/30 11:26] – raivo.sell
+++ en:examples:motors:stepper [2010/02/04 12:30] (current) – removed mikk.leini
@@ Line 1: / Line 1: @@
-====== Stepper motor ======
-Stepper motors can very generally be divided into unipolar and bipolar steppers.
-Unipolar stepper motors are characterized by their centre-tapped windings, which
-divide two coils into four. Stepper motors have neither built-in brushes nor internal
-electronics, meaning that all commutation must be performed externally. The most
-common commutation type is the open-loop mode: the motor driver energizes the
-coils following a certain pattern, but uses no feedback. Steps can be missed in case of
-motor shaft torque overload. Missed steps cause inaccurate positioning. Bipolar
-stepper motors usually have four wires and two separate coils inside; they have many
-features similar to those of unipolar steppers. Unipolar stepper motors can be run as
-bipolar stepper motors, but not vice versa.
-{{:examples:actuator:unipolar_model.gif|}}
-===== Electrical connections =====
-Table of stepper motor windings.
-^ Pin  ^ Unipolar winding ^ UP PORT   ^ Bipolar winding ^BP PORT   ^
-|  1  |  1   |    |  1a  |  PB0  |
-|  2  |  2   |    |  2a  |  PB1  |
-|  3  |  1a  |  PE0/PE4  |  1b  |  PB2  |
-|  4  |  2a  |  PE1/PE5  |  2b  |  PB3  |
-|  5  |  1b  |  PE2/PE6  |  |  |
-|  6  |  2b  |  PE3/PE7  |  |  |
-  - Make sure all power is off.
-  - Connect the actuator board and main board with a 26-pin cable.
-  - Connect the stepper to the actuator board, as shown in Figure. Note: The unipolar motor cable must be properly connected (wires a and b, according to figure 1, connects to pin 1 and 2 on connector UNI1 or UNI2).
-  - Connect the JTAG converter with the ATmega128 main board and the PC.
-  - Finally, connect the power to the main and actuator boards.
-{{:examples:actuator:stepper.jpg?500|}}
-===== Test programs =====
-{{:examples:hex:bipolar.hex|Bipolar.hex}} (moves 100 steps one direction and 100 stepes opposite direction in endless loop)
-===== Example code =====
-<code c>
-/*-------------------------------------------------------------
-Title:		Bipolar stepper motor with Actuator Board
-Date:		080328
-Ver.:		1.1
-Compiler:	AVR-GCC
-Target:		ATmega128
-Hardware:	Main board, Actuator board, bipolar stepper
-Author: 	Maido Hiiemaa / Raivo Sell 2008
-Notes:	Optimization -02
-Description: Drives stepper in both directions by 100 steps
----------------------------------------------------------------*/
-#define STEPDELAY (50) // one step delay
-#include <avr/io.h>
-#include <util/delay.h>
-//global variables to store commutation patterns
-static unsigned char bipolar_pattern;
-//Function prototypes
-void bipolar_clockwise(int number_of_steps);
-void bipolar_counter_clockwise(int number_of_steps);
-///////////////// Functions //////////////////////////////////
-void bipolar_clockwise(int number_of_steps){
-	int i;
-	for (i=0; i<number_of_steps; i++){ //repeat for each step
-	bipolar_pattern = bipolar_pattern << 1;
-	//shift pattern to the left
-	if (bipolar_pattern>8){ bipolar_pattern=1; }
-	// alter b'10000' to b'0001' if needed
-		PORTB &= 0xF0; //zero last output (low bits)
-		PORTB |= bipolar_pattern; //apply new pattern
-	_delay_ms (STEPDELAY); //wait for the motor to complete the step
-	}
-	PORTB &= 0xF0; //turn off motor
-}
-void bipolar_counter_clockwise(int number_of_steps){
-	int i;
-	for (i=0; i<number_of_steps; i++){//repeat for each stepbipolar_pattern = bipolar_pattern >> 1;
-	//shift pattern to the right
-	bipolar_pattern = bipolar_pattern >> 1;
-	if (bipolar_pattern==0) { bipolar_pattern=8; }
-	//alter b'0000' to b'1000' if needed
-		PORTB &= 0xF0; //clear low bits
-		PORTB |= bipolar_pattern; //apply pattern to output
-		_delay_ms (STEPDELAY); //wait for the motor to complete the step
-	}
-	PORTB &= 0xF0;//turn off motor
-}
-///////////////// Main function //////////////////////////////////
-int main(void){
-//output ports initialization
-	DDRB=0xFF; //output port for bipolar stepper drive signals
-	PORTB=0; //initial PORTB output
-	bipolar_pattern=0x01; //initial pattern for bipolar stepper
-	while(1){
-		bipolar_clockwise(100);
-		bipolar_counter_clockwise(100);
-		}
-}
-</code>

en/examples/motors/stepper.1254310003.txt.gz · Last modified: 2020/07/20 09:00 (external edit)