Coming Soon: Teensy-LC (low cost Teensy)

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mcsarge said:
OK, I will try with the large resistor on SDA as you suggest, but I probably can not do it until Sunday night. Going to see my daughter get her graduate degree from Clemson on Friday! Thanks very much for all the help, I really appreciate it!

Matt
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I have it working!

I tried the larger 10K resistor and that did not seem to change anything. I figured I would try the i2c_t3 library and after I converted my code to use that, it started working!

Thanks again for all the help across the board, I do not think I would have stuck with it if it wasn't for nox771 and Paul, many thanks!

Matt

Here is the trace of it receiving the data.
Spectra_to_TeensyLC_Slave_i2c_t3.jpg
 
Hey all,
I've done a quick search over the thread, but was unable to find any info:
Can the Teensy-LC do the HID Joy/Mouse/KB emulation like it's older siblings?

And now for a suggestion: When you do these things, you might want to do an update to let all your kickstarters from previous projects know you are doing something new and cool! I managed to miss both the 3.1 AND this for ages simply because I didn't think to check :)

(I use my Teensy 3.0 as a 15 Pin Joystick emulator for an old pair of CH Flight foot pedals. Currently expanding it to do whole buch of custom keystrokes to aid in playing OOLITE)

John "Cheshire" Parker
 
cheshire said:
Can the Teensy-LC do the HID Joy/Mouse/KB emulation like it's older siblings?
Click to expand...

Yes, it can do all the same USB features as Teensy 3.0 & 3.1.

And now for a suggestion: When you do these things, you might want to do an update to let all your kickstarters from previous projects know you are doing something new and cool!
Click to expand...

Yeah, that's a good point. I really haven't looked at Kickstarter over the last year or two.
 
PaulStoffregen said:
Yes, it can do all the same USB features as Teensy 3.0 & 3.1.



Yeah, that's a good point. I really haven't looked at Kickstarter over the last year or two.
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W00t! That's excellent! (I figured they would)

Bwahaha! Those are cheap enough I can use them as "disposable" for some of my projects.

Next payday I'll have to place an order.
 
Hi
I need to be able to define an accurate Reference voltage for an LC, I'm still working out if its 2.5V or it could be 1.0V - whats the recommended way of doing it.
I've done a search on this thread for using the AREF pin, and I couldn't find anything/
https://forum.pjrc.com/threads/28380-DC-signal-generator-using-the-DAC

Looking at a 3.1 posting it suggested connecting a LM336 to Aref with enough current to over-ride the internal 480ohm R connecting to VDD - does that still hold?
thanks
 
Hello Paul-
Brand new here, and still trying to grasp all the capabilities of the different versions. You have an excellent table for the Teensy LC in this thread, but nothing comparable for 3.1 and 3.2. I can extract most of it from the "3.2 & 3.1 New Features" technical specs, but nothing about INTs and Output sourcing current for the different pins. It took me a while to infer that any pins on the 3.1 and 3.2 can be interrupt enabled by reading posts, but nothing documented. If there are tables out there that I haven't found, please hold my hand and guide me. Thanks.
 
Yes, there's a tremendous number of details which add up to a ton of information to communicate.

When we add a high-end Teensy++ 3.x, I'll probably make a big table comparing all the options. But it's difficult to make a huge table that shows everything and is still easy to read and understand at a quick glance.
 
Is there any way to add an external reset button to an LC? Pressing the program button hangs the sketch, is that normal? I'm resorting to power cycling the board which seems crude.
 
The button on Teensy LC (and all Teensy boards) is for entering programming mode. It's *not* a reset button for restarting your program!
 
*YOU* can add a reset button. There should be a pad on the bottom. Just have your switch connected to it and GND. GND resets it.
 
xxxajk said:
*YOU* can add a reset button. There should be a pad on the bottom. Just have your switch connected to it and GND. GND resets it.
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The LC does not have a pad on the bottom for reset. Only the 3.1 and 3.2 have such a pad (and it is in a different location between the two). The only pads underneath the LC are the D-/D+ for USB, and the VUSB/VIN connection pad.
 
Maybe this was covered, but I can not seem to find the correct information.

I would like to use the Adafruit Trinket LiPo Back pack on my LC. It has a 3 connections - GND, Bat and Vin. It automatically switches from battery power to USB power when the USB on the trinket is plugged in. Would it be possible to do the same with the LC? I see that we have the 5V from the USB available, would connecting the other two pins to ground and Vin work?

I guess the real question is can I power the LC from a 3.7V batter using the Vin pin? It reads 3.7-5.5V, while the Vbat pin on the Teensy allows 3.3-16V.
 
The Adafruit Trinket Pro LiPo backpack won't fit directly on the LC, you would have to wire the 3 pins and place the backpack elsewhere. You would have to cut the trace between VIN and VUSB like you would have to for the 3.0/3.1/3.2 (https://forum.pjrc.com/threads/1922...ng-VIN-from-VUSB-Teensy-3-0?p=44024#post44024).

If you haven't bought the backpack, you might want to look into onehorse's custom board for the 3.0/3.1/3.2/LC. He has two boards, the original one would change smaller batteries, and his newer board charges larger batteries:
 
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Beautiful,

Thanks, I have not yet ordered the backpack, but onehorse's boards may be the answer.

One followup - if I power the LC from a 3.7V battery connected to Vin and do not pug a USB in, should it startup and run correctly? I know if I want to have the USB and the batter in at the same time, I need to cut the trace. Then if I need to reprogram the LC, I need to keep the battery plugged in while I connect the USB.

Matt
 
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You can power the Teensy from a 3.7 LiPo battery. With the LiPo battery charger soldered to the Teensy, even without the battery, the Teensy can be programmed from just the USB cable since the USB provides power to the charger chip, which supplies 4.2 V to Vin even in the absence of a battery. You'll get at most 100 mA this way but enough to program the Teensy.
 
Beauty - I am thinking of just using a battery connected to my board directly for now, which a user would have to unplug and charge separately, but adding the option of getting one of your boards to have a simple charge system all included.
 
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