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Author Topic: logic high == +5v ?  (Read 369 times)
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Hi,

I bought a Pololo A4988 stepper driver to configute microstepping I need to bring some pins to logig high or logic low (which they are in by default).
I can simply connect them to +5V? Or is there a difference between bringing them to high via a digital PIN and connecdting them to +5V rail?


Thanks
Robert
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Logic High = 1 = +5V.
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Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
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Thanks. Just wanted to make sure I don't fry the driver.

Robert
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Nearly all modern stuff is CMOS, and CMOS logic levels go right to the rails.  (This wasn't true
for older TTL logic families which used pull-up resistors for logic high)
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CMOS uses transistors to pull the outputs low or to drive them high also.
http://www.ti.com/lit/an/scla007a/scla007a.pdf
See figures 2 & 3 on pages 1 & 2.
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Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

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