I've got a cheapo Nano clone, the digital output of the pin only hits 4.6-4.8v high, but then drops to only 1.3v or so for the low. Just testing really, with the blink example changed for 5 sec on, 5 sec off to allow for reading the voltage. I'm pretty sure this is messing with my circuit - I'm using this as the hv1 input to one of those bi-directional logic level shifters, trying to convert the 5v to 3.3v. what I want to see is Dout goes high, converts to a 3.3v high. Same setup works fine on an Uno. But not the clone nano. The Uno hits 5.1 high, 0 low though. Would the 5.5 hi 1.3 lo be my problem? Would a pulldown resistor on the Dout of the nano properly force it to 0v nd possibly fix my problem? Thx all!

What's connected to the output pin? Can we see a schematic? What happens when nothing is connected except your meter? I'll look for the output specs, but anything below 1.5V on an input is read as low, and anything above 3.5V will read high. In-between is undefined and can read high or low. ...OK, Output-low should be 0.8V or less at 20mA. Output high should be 4.1V or more at 20mA. That's with a 5V power supply. More current makes those "worse" (unspecified) and less current makes them "better". That output specs are ALWAYS more strict than the inputs so if you write low you ALWAYS read low (with a connection to a similar device) and if you write high you ALWAYS high. (That's assuming the voltage & current are within spec.)

[image] beamsbox: the digital output of the pin only hits 4.6-4.8v high Normal behaviour if powered from USB. A classic Nano simply uses a diode for USB backflow protection, which drops about 0.4volt. So VCC of a Nano on USB power is about 5 - 0.4 = 4.6volt. An Uno/Mega uses a more complicated circuit there, with an opamp and mosfet. So VCC is much closer to USB voltage on those boards. Not that it matters for most projects. LOW should be close to zero though. Did you set the pin to output with pinMode. Leo..

[image] beamsbox: I'm pretty sure this is messing with my circuit How would we know? Can you provide a schematic? [image] How to make a schematic you can post. Introductory Tutorials When you submit a question on the forum you will usually need to add a schematic (circuit diagram). The tutorial that follows will explain some ways to create a useful image; however lets start by explaining how to add the image to your post. Its easy. Having created the image all you need to do is : Save the image somewhere convenient - maybe your desktop Start your post, and place the cursor (insertion point) where you want the image to be shown; [upload image to forum] 3: click th…

Hi, [image] Wawa: Did you set the pin to output with pinMode. Leo.. Good question. @beamsbox can you please post your code? To add code please click this link; [image] How to get the best out of this forum IDE 1.x See also FAQ - Arduino Forum for general rules on forum behavior and etiquette. Hello, Welcome to the Arduino Forum. This guide explains how to get the best out of this forum. Please read and follow the instructions below. Being new here you might think this is having rules for the sake of rules, but that is not the case. If you don’t follow the guidelines all that happens is there is a long exchange of posts while we try to get you to tell us what we need in order to help you, which is frus… Thanks.. Tom... :smiley: :+1: :coffee: :australia:

Tom, John, code is not really in question, literally using the blink code example modified for 5 sec, as stated in first paragraph.

Dvd and Wawa, thx for the helpful responses. The output is going to one of these bidirectional level shifters. Looks like just a MOSFET. https://www.google.com/search?q=hiletgo+level+converter+schematic&oq=hiletgo&aqs=chrome.1.69i57j69i59j0i512l8.4179j0j7&client=ms-android-google&sourceid=chrome-mobile&ie=UTF-8

[image] beamsbox: Same setup works fine on an Uno. But not the clone nano. Just to mention that pins A6 and A7 on an UNO can work as digital I/O, but on an Nano, they are analog only.

To be a bit more clear, it is this level shifter that only seems to work with the Uno. It passes the 5v digital high from the Uno and converts to a 3.3 v pulse coming out the L1 pin. Same setup but using the Nano, no 3.3v pulse output from the L1 pin. It just remains in the 3.3 v state, as it does when nothing is hooked up to the H1/L1 pins at all.

[image] beamsbox: To be a bit more clear You have to do better than that. Some pins of the classic Nano are different. Pin13 is one of them. It has no buffer for the built-in LED, so can give problems when used as input. And there are Nanos and Nanos. I assume you have a 16Mhz classic Atmega328 Nano. But there are many others with different logic voltages. Some dumb-ass called them Nano too. A mosfet level converter is just a switch. How LOW the pin will go still depends on the load on the other side. Leo..

Hi, Have you tried changing output pin on the Nano? Can you please post a image(s) of your Nano? Thanks.. Tom... :smiley: :+1: :coffee: :australia:

Nano clone digital out only drops to 1.3v [Solved]

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johnerrington June 2, 2022, 2:01pm 4

How would we know? Can you provide a schematic?

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Nano clone digital out only drops to 1.3v [Solved]

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