L297 & L298 Schematic !!!

[Ruby]

Hi everybody. I am trying to build a robot with 2 bipolar stepper motors. I ordered 2 pairs of L297 and L298 but i have a problem ; i don't know how to connect them. I have schematic but i am not sure... I need help. I want to control it by using parallel port.

[Soeren]

Hi,

Hi everybody. I am trying to build a robot with 2 bipolar stepper motors. I ordered 2 pairs of L297 and L298 but i have a problem ; i don't know how to connect them. I have schematic but i am not sure... I need help. I want to control it by using parallel port.

The schematic looks fine, so what exactly do you need help with?

[Ruby]

Hi. I can send pulses from parallel port 3.7 volt (Pin number 2 to 9). But how will i connect to L297? And how will i connect diodes ; which diodes?

[Soeren]

Hi. I can send pulses from parallel port 3.7 volt (Pin number 2 to 9). But how will i connect to L297?

Like shown in the datasheet and the schematic you posted (the pins in the left side).
You do know how a stepper works, right?

And how will i connect diodes ; which diodes?

Like in the schematic, use fast diodes that can handle the current.

[Ruby]

I now how they work. Where and how can i find the diodes that i need? I searched in ebay but i don't know what and which one order? Under the page is writing 2 and fast ; i guess 2 means 2 Amperes but what about fast?

[Soeren]

I now how they work. Where and how can i find the diodes that i need? I searched in ebay but i don't know what and which one order? Under the page is writing 2 and fast ; i guess 2 means 2 Amperes but what about fast?

It means that you are 2 fast to shoot of questions that you should be able to answer yourself 

You don't have to guess about the current, since the datasheet clearly says "2 A".

What you cut out says:
RS1 = RS2 = 0.5 Ohm  (that's the current sense resistors)
D1 to D8 = 2A Fast diodes:  V_F <= 1.2V @ I = 2 A  trr <= 200ns

So there you have it... trr means Time of Reverse Recovery and that's the critical parameter.
I'll save you the work (and further lazy-posts) by suggesting BYV27, but do try a cup of Google every now and then - you learn nothing by being spoon fed.

[Ruby]

I looked but i wasn't sure...
What about this diode ; do u think will it work?


And i was thinking to add diode in parallel port in case of protecting...
What do u think?

[Soeren]

What about this diode ; do u think will it work?

No, it's got a trr of 500ns.

Don't be scared of Google - Researching, reading datasheets and learning is half the fun of electronics.
Please don't post more "alternatives", just grab a bag of BYV27 and be done with it.

And i was thinking to add diode in parallel port in case of protecting...
What do u think?

I think that you probably shouldn't connect anything to a PC until you know what you're doing and how the components work - better use a small $2..$3 microcontroller, as it's much cheaper to replace. When all is tested OK,

If you connect things up right, there's no reason for protecting the port, as the inputs to the L297 is pure logic and if you don't connect things right, it may be the "protection" that wreaks havoc anyway.