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How to control an H-bridge from Arduino

I bought a LMD18200T H-Bridge but do not understand how to manage the connections from an Arduino. I am using an Arduino Wee which runs at

3.3V and offers digital output and PWM.

What are the minimum required connections for this H-Bridge?

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The following seems straightforward:

Pin 2: Output 1 -> voltmeter (eventually to DC motor) Pin 10: Output 2 -> voltmeter (eventually to DC motor) Pin 6: PWR Supply -> 8V power supply Pin 7: Ground -> Ground from power supply Pin 3: Direction Input -> Arduino digital output HIGH

I also tried:

Pin 4: Brake -> digital LOW Pin 5: PWM Input -> Arduino analog output (value 255)

I didn't do anything with the "Bootstrap" pins.

One part I don't understand is the PWM Input. Is that required? Is

3.3V sufficient?

Any clarity you can lend to this would be appreciated. I was not able to find anyone documenting this H-Bridge wiring to an Arduino.

Thanks, Damien (U. Penn, Philadelphia)

Reply to
Damien
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The PWM pin is how you turn the chip on and off. Nuttin' works without it.

PWM is a digital signal, so you just want to connect it to a PWM output of the Arduino, saving the analog outputs for something else. Looking (briefly) at the spec sheet for the 182000 you want a TTL-level (or better) signal for PWM. If the Arduino Bee only puts out 3.3V there you might opt for a level shifter. Most any CMOS gate chip running at Vcc will trigger HIGH on a 1V or higher, and will output Vcc.

My advice is to Google around to find some circuits for a Basic Stamp, OOPic, or other controller that use this chip. That will provide a baseline for you.

Finally, bear in mind that the LMD18200T is a DMOS device, meaning it requires Vs of at least 10 volts, and preferably 12, before it comes alive.

-- Gordon

Damien wrote:

Reply to
Gordon McComb

Thanks for the good advice. My main problem was that I was using less

12V.

That's too much power for this motor, so it looks I chose the wrong H- Bridge. The L293D looks promising, and more popular:

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Damien

Reply to
Damien

Please note that the SN754410 is a direct functional replacement for the old trusty L293D. It has a higher current capacity to boot.

-Wayne

Reply to
Wayne C. Gramlich

And cheaper. A buck and a half at Jameco. That's half or less than what most places are asking for the L293D.

For the OP, there are plenty of tutorials for using the Arduino and L293, and interfacing and programming for the 754410 would be identical.

-- Gordon

Reply to
Gordon McComb

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