Teensy 3 Newbie questions

Status
Not open for further replies.

tdg8934

Active member
I received my Teensy 3 today with the Teensyduino Tutorial kit. Surprisingly I got a breadboard too with my order so that was nice.

I used to have a Teensy 2++ a year or so back but lost all my micro-controller stuff in a move to Michigan this year.

I have never worked with 3v inputs and wondering if the Tutorial kit will still work with the Teensy 3.

Is there a place to start with this? I installed the Beta 6 Windows software for Teensy 3 and see the blinking LED on it so that's good (after I set the Arduino IDE for Teensy 3). Wow it has an overclock of 96 MHz too!

I'm concerned about connecting a LED to the Digital Output. Can someone direct me on this as it is 3.x vdc and not 5 (using a resistor and LED for that). Is the resistor needed then?

Just a little help knowing what to do next and it safe for this Teensy 3.

I learned a little C and rusty on Arduino code but I'll get it. I just want to run through some tutorials again that are safe for the Teensy 3.

Thanks!

Tim Gilmore
 
Teensy 3 runs at 3.3 V from its onboard regulator. The forward voltage drop across a typical LED depends on the color, ranging from 1.7 V (for red color LEDs) to 3.5V or more for blue and white types. You should always use a resistor with the LED to limit current (9 mA maximum direct from a Teensy 3 pin) but the value of the resistor will vary depending on the LED type.

As a concrete example, say you have a red LED with Vf=1.7 V and you want to run 5 mA through it from your Teensy 3 pin. You want (3.3 V - 1.7 V) = 1.6 V across the resistor, so by ohm's law V=IR or R = V/I = 1.6 V / 0.005 A = 320 ohms. In practice, you will not get precisely 5 mA, because there is some internal resistance in the chip so it will not produce quite 3.3V under load, maybe you'll get about 4 mA or so, but you should still be able to see the LED.

If you use a LED directly on a port pin without a resistor, you run the risk of damaging the chip due to overcurrent, although I'm not sure exactly what would happen- not recommended in any case.
 
Last edited:
Windows 8 with Teensy3 (not seeing Arduino program from Teensyduino software)

OK thanks I just wanted to be sure about the 3 v.

However, I now have a more serious issue.

I installed the Teensy 3 beta 6 software for Teensy 3. I have a new Windows 8 laptop I'm using this on. I ran the TeensyDuino software and had problems installing the driver. I found the Windows 8 note and followed it to get the driver to install on Teensyduino. However, once it gets past that point it can't find the Arduino program from the Teensy 3 beta 6 directory. As a test I downloaded the latest Arduino UNO software and Teensyduno WAS able to find the Arduino program and installed ALL the working libraries and I ran the Blinky program and changed the LED command to pin 13 and it worked.

I'm don't think it is seeing the Teensyduino 3 stuff running the Arduino Beta 6 arduno program since I think the Teensyduino software installed everything to the 1.0.1 Arduino UNO software.

I saw the rest of the Windows 8 note about the Testcert.cer and Arduino.inf and arduino.cat files but can not search and find these files. Is there something I'm missing here?

Thanks
 
Thanks JBeale!

That worked. I'm up and running on Teensyduino 1.10 and Arduino Teensy 3 - Beta 7 on Windows 8.

Time to run through the tutorials this weekend.

Thanks again,

Tim

Teensy3 screen at 96MHz.jpg
 
Status
Not open for further replies.
Back
Top