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I will design a circuit that includes parallel port and three stepper motor+obstacle circuit <I will attach the circuits for them>
My question is how I can connect the parallel port via these circuits please, I know I must use a decoder but I cant know how that will occur.
the circuit for the stepper motor will be used three times.
please help me in a quick time.



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don't know if it will help but I'd consider using 3 of the parallel port lines to clock 3, 4-bit serial/parallel converters, each of which would be attached to a motor driver chip.  This will leave you a minimum of 5 parallel port lines available for your obstacle circuit (which could also be serialised in the other direction). 

The software requirements shouldn't be too onerous as the stepper motors require on/off times to be in the millisecond range whilst the parallel port is capable of considerably higher speeds.


Actually, you only need one parallel port line for serial data if the serial/parallel devices are cascaded, together with one clock line.

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Yes, you can use L298 and L297 for stepper control. These chips are usually used when you have substantial current needs. The ULN device you have posted will provide enough current for most smaller steppers. I have discussed steppers in a few different threads on this site in the past. Please try a search for them.
Here are a few of them:




Please also find the links in these posts for additional resources on the web.


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The only difference between connection of 4 wire and 6 wire is that you do not connect the center tap on the coils of a 6 wire stepper. This makes a 6 wire stepper a 4 wire stepper.
There are schematics all over the internet for the L297 and L298 combinations.
Here are links to a few of them:



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There is probably some literature that can be found for your motor, but the best way I have found is to measure the resistance between the wires or terminals on the motors. The windings are all going to have the same resistance. This will tell you which ones are the windings and which ones are the center tap. As far as deciding which is the left and which is the right, this will determine direction. Without a diagram, you might have to perform a little bench checking to determine that you are on the right track. If you have a diagram for the motor with some markings such as a and b, you just match up the numbers and/or letters to know you are not wiring one coil backwards. You cannot hurt the motor. Just swap the wires if needed. On most motors that I have bench tested, the connectors are pretty much in order. In other words, the left pin for the first winding is on the same direction as the left pin for the second winding. This might help you with direction.
This probably does not sound like much help, but without literature on the motor, this is really the easiest way to solve the problem of matching the winding direction on both coils.


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Hi again
I have some questions on the circuit:
1- SYNC, HOME, Vref and Control pins >> where I must connect them to a microcontroller or where ??  :-\
2- Enable, RESET, Half/Full, Clock and CW/CCW are will connected to a microcontroller to be controlled there, can I know what are the sequences that I must write for them by the microcontrolller to make the motor rotate forward or backward??
3- In l298, what is the value for Vs, is it 9V??
4- In l298, pair of diodes>> one will connected to a 9V, the other to a ground while they connected together?? 

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The L297 and L298 combination takes care of the sequence to the stepper.

The address below gives a good description of how to do this with a pic micro controller.



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Thank you Map, am so happy with this link, but I have a little question  ;D
1- please tell me how I can connect a motor with 6 wires to this design?? and what is the arrangment of 2,3,13,14 (output pins for L298) that give me the true connected via wires of the 6 or 4 wires motor??
Hope that my question is clearly :-\

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I really cannot answer this question clearly. Please look at my previous responses that will help you determine this.
For example, if you take ohm readings between all of the pins on your motor, You will have two different values. Let's use 5 ohms and 10 ohms as an example since I do not know what they are on your motor. Any 2 wires that read 5 ohms are measuring one coil. It is a measurement of center tap to the end of the coil. Any wire that measures 10 ohms, would be the two coils which are connected together by a center tap.
A drawing below.

This is the best I can do with a motor that I have no data sheet.
Hope it is helpful. Have you looked for your motor in a web search to see if there is a data sheet for it?



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Can you give some information on the steppers you use? Perhaps there is some information on the internet. What is the make and model name on the motor? We really need to find the specs on your motors before answering the questions about power supply rating, etc.


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You should go to:  http://www.alldatasheet.com/
and download the free data sheets for these devices and compare the specifications. You should always refer to the datasheets whenever you wish to make a substitution.


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