Need Help!- L297 - L298n

[reuven81]

L297&l298n.jpgHi everybody.
I have problem with wiring L297 - L298n. I did everything as in datasheet but i didn't get anything but a burning smell.
Can someone please tell me what did i do wrong?
I am trying to control bi-polar stepper motor by sending pulses from parallel port to L297
CW/CCW , half/full step ,reset , enable and Vref are connected to 5 volt
Control to ground
I am sending pulses to Clock from parallel port ( 3-3,5 volts )
Instead of 36 volts i am using 24 volts.
I have 4 wired stepper motor and how can i connect them to L298n?
Thanks

[Edison4]

RS1 and RS2 should be 0.5 Ohm resistors rated at least 3 Watts, preferably 5 Watts.

Vref should NOT be connected to 5V! The voltage on the Vref pin sets the motor current per this formula: Stepper motor current (Amps) = Vref(volts) * 2.

For example, to set the motor current to 1.0 Amps per phase, the voltage applied to Vref should be 0.5 Volts.

The Vref voltage is usually derived by using a resistor divider from the 5V. Using a potentiometer in the resistor divider lets you adjust the Vref voltage.

ED

[reuven81]

Thanks.
I check the the motor and it needs 6.4 ohm so i need Vref 3.2 volt.
I build is again but this time without L298n and and i put 4 leds to the output of the L297.
First i put them between every pin and ground ; but only 2 of them worked , also i changed the CW to high but the same and when i send pulses to clock they went off.
Then i put pair for each output ; one pair between 4 and 6 numbered pin but opposite directions ; same same....
Why can it be?

[edmundopt]

Hello

please download datasheet of L297 from http://www.st.com/stonline/books/pdf/docs/1334.pdf .

Page 7 clearly mentions that VRef maximum voltage is 3.0Volts!

Use the following formula VRef = Ohms of Sense Resitor * Motor Amps

[bhagwat shirish]

Hi,
Please use ref less than 5 V Dc say 2,5 V.
Use non inductive sense resistors.