Teensy 3.1 Defective?

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eric1084
 
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Teensy 3.1 Defective?

Post by eric1084 »

Hello, I bought a Teensy 3.1 from adafruit at Sept,21,2014 https://www.adafruit.com/products/1625. And It just arrived a few days ago. And for some strange reason, the 3.3v pin on the Teensy doesn't work(I even measured it with my multi-meter, it displayed 0.3v. That means it works, but for some reason only outputting 0.3v) And also, when trying to pull data from Analog Pins, it keep giving me random numbers between 70-200... And it can't even read and print the data from a potentiometer to the serial output.... Please help, thank you.

Here is the example code I used:
http://arduino.cc/en/Reference/analogRead

Order number: 590579-2537989176

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adafruit_support_mike
 
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Re: Teensy 3.1 Defective?

Post by adafruit_support_mike »

Could you post a photo of the Teensy please? 800x600 images usually work best.

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eric1084
 
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Re: Teensy 3.1 Defective?

Post by eric1084 »

Ok, Here is the photo(I took the photo with my iPhone.) But it exceeded the 1MB file limit, so I shrinked it down to 800x600 :-)
Teensy_Photo
Teensy_Photo
teensy_shrink.JPG (287.95 KiB) Viewed 749 times
Also, I attached the photo of the serial output(When I attach my potentiometer and kept it still, and it is just giving me random numbers...)
Seerial_monitor
Seerial_monitor
Capture.PNG (6.92 KiB) Viewed 749 times
Also, here is my Code:

Code: Select all

void setup()
{                
  Serial.begin(9600);
}

int val;

void loop()                     
{
  val = analogRead(A0);
  Serial.println(val);
  delay(250);
}

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paulstoffregen
 
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Re: Teensy 3.1 Defective?

Post by paulstoffregen »

Can you try measuring the pot's voltage at the pin on Teensy?

In other words, while this is running and you've got the numbers scrolling on your screen, touch the red lead to the pin above Teensy, and the black lead to ground (like the USB connector shell).

Of course, also double-checking the soldering of that A0 pin, and the 3.3V and AGND pins. Results like you're seeing are very likely due to one or more of those pins not properly connected.

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eric1084
 
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Re: Teensy 3.1 Defective?

Post by eric1084 »

Ok, I just tried it, still no luck... I also tried to measure 3.3v and Ground with multimeter, reading 0.3v

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paulstoffregen
 
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Re: Teensy 3.1 Defective?

Post by paulstoffregen »

Something certainly isn't right.

Teensy can't possible be running and sending data to the serial monitor with only 0.3 volts. You're clearly getting some data, even if incorrect, which means the processor and USB are working, so the board must have good power to be doing that.

Why you're seeing only 0.3V when you measure is a mystery. From only the info here, I can't know why. But I can tell you it couldn't possibly be actually only 0.3V and able to send anything to the serial monitor window.

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eric1084
 
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Re: Teensy 3.1 Defective?

Post by eric1084 »

Well, Then what is wrong here?(Just to make sure, I'm measuring AGND and 3.3V(100 ma max) which is located 1 pin up above pin 23

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paulstoffregen
 
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Re: Teensy 3.1 Defective?

Post by paulstoffregen »

Without the board here, and with only the info in these messages, I can only guess.

Here's 2 guesses:

#1: Perhaps your multimeter is set to AC voltage? You need it to be on DC to measure this.

#2: Perhaps you're not making a connection to the actual voltage, maybe due to soldering problems? On the right hand side of the Teensy (opposite the USB) are 5 extra pins. The center is GND. The one right below is +3.3V. Maybe try touching those 2 pads with your multimeter.

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eric1084
 
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Re: Teensy 3.1 Defective?

Post by eric1084 »

Hi, I'm pretty sure soldering is not the problem(I'm using the header which is included with the teensy), and the right hand side's pad's voltage is normal(3.34v)
My guess:
Perhaps that the PCB board of the Teensy damaged, etc, causing a few pins not connected to the cpu? Is that a possibility?

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adafruit_support_mike
 
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Re: Teensy 3.1 Defective?

Post by adafruit_support_mike »

Just to verify, have you soldered the pin header to the Teensy PCB?

The photo shows the pin header's plastic spacer on the top of the PCB, and we usually see that when someone has just plugged the header through the holes and into the breadboard.

That doesn't work. You have to solder the header to the PCB to get an electrical connection.

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eric1084
 
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Re: Teensy 3.1 Defective?

Post by eric1084 »

OH! Sorry, that is my fault. I did not double check...

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