Teensy 3.5/3.6 Breakout board to test things with.

Wow that was fast :). Its about 4.5 by 4.5 and for the short run it 3 for 180. Know its expensive but had to try. Have a simpler design that just breaks out the top pins that was about 3 for 50. Parts are the cheapest probably around 20 - had a lot of pieces laying around. Proabably could be cheaper because like I said I had no idea what I was doing and I added a lot of pin breakouts.
 
Hi Mike,

Looks like you are having fun, which is the main point. I have downloaded Kicad but have not tried it yet. I have been playing around with Diptrace for a few years now. So far all of the boards I have done are 2 layer boards.

I totally understand the desire for the different busses to be brought out to their own set of pins. The problem I had was then deciding which ones to bring out. For example there are 6 serial ports, plus several SPI(3), and several I2C(3 or 4)... I have never used CAN so have not considered that yet. Then there is I2S... The problem I was running into is for example suppose you wish to use I2S and SPI object, then you need to change to use alternate pins for SPI... So many choices...

A lot of my boards were influenced by some of the first boards I used when working on robotics, which included the Lynxmotion BotBoard2, which brought out all of the IO pins of the BasicAtom Pro 28, to 3 pin servo headers, which then allowed you to do lots of things. They did have a couple of special purpose connectors, like an easy way to add a receiver for PS2 receiver, but for the most part they left all of the pins general purpose. So my first Teensy board was modeled after this, except more pins and XBee connector... Next one replaced XBee adapter with Arduino shield connectors... Maybe at some point should create a new one like that but maybe make have the Arduino Mega form factor? Or maybe the old Seeedstudio Mega factor? ...

Again looks like your board could be a lot of fun and gives you lots of options to play around with. Let us know how your new board works out!

Kurt
 
Hi KurtE

Thanks for the words of wisdom. After fiddling with this version think I am going to go over to diptrace. Just took a look at it and it looks easier to use than KiCad. Based on your comments you gave me a lot to think about for the next version. If this version works I still have two blanks, if I don't mess up the soldering. I should get the boards today (I hope).

Mike
 
Update

Wow that was fast :). Its about 4.5 by 4.5 and for the short run it 3 for 180. Know its expensive but had to try. Have a simpler design that just breaks out the top pins that was about 3 for 50. Parts are the cheapest probably around 20 - had a lot of pieces laying around. Proabably could be cheaper because like I said I had no idea what I was doing and I added a lot of pin breakouts.

I did a redesign so it is now on two layers and its about 4x4 now. Some traces were not connected correctly so just redid it. Price is now down to 3 for 80 on OSHPark.
 
Sounds good. Pictures?

I have good luck with OSHPark who are reasonable with their prices, especially for smaller boards. My guess is digistump (https://pcbs.io/), the prices would be lower. But recently their website showed they were for sale and now it does not. So not sure if it was sold... Their price is sliding from $4-$3 per square inch. Over 20 square inch is $3. so at 16 square inch, my guess is maybe $3.50 per sq inch would be about $56.

Or if you can get the board to be under 10x10cm you can order direct from China at Seeedstudio (https://www.seeedstudio.com/fusion_pcb.html), the price for 10 of them is about $22, plus shipping.
 
Thanks for the info for the pcb manufacturers. The layout is the same as before. Had to fix some connections that were not made - my problem still learning kicad. I should be able to shrink the board so I can get boards from seedstudio. I did find some low profile female sockets so the under side pins should fit better. I will post some pictures of the finished board probably in about two weeks. The long pole in the tent is the pcb. Don't expect to get it until mid-November.
 
Sounds good. Pictures?

I have good luck with OSHPark who are reasonable with their prices, especially for smaller boards. My guess is digistump (https://pcbs.io/), the prices would be lower. But recently their website showed they were for sale and now it does not. So not sure if it was sold... Their price is sliding from $4-$3 per square inch. Over 20 square inch is $3. so at 16 square inch, my guess is maybe $3.50 per sq inch would be about $56.

Hmmm, after some digging, I see the forsale page is still live, if people were wondering way it is/was for sale: https://pcbs.io/forsale.php

I did run across pcbshopper which compares the prices of several pcb manufacturers: http://pcbshopper.com/
 
@MichaelMeissner thanks for the link to pcbshopper works great. Putting some basic configs can drop the board price down dramatically. @KurtE received the PCB today and populated enough to start testing. I have attached a picture. Did find a couple of things have to fix but workable.

20161105_210210.jpg
 
Hi all

Thought I would give you an update with the board since I have been doing some testing. The top layer pin connections work fine and tested several of the analog pins with a flex sensor and they work fine. The RX/TX work fine with a Neo-M8N GPS using the NeoGPS library. The TinyGPS++ lib won't work with GNSS - its only geared to read GPS strings. Did find a lib that would work though that was modified. Still have a couple of issues - most easily resolved. Like connecting the vin and ground pins to the associated buses (you can see the jumpers in the attached picture). Have to move the 4 pin header over a bit near the usb connector. Did have one pin not connected. Also had the connections on the vbat, reset and pgm reversed. The biggest problem is with the underside pins circled in the picture - they don't seem to line up with the underside of the teensy - not sure if they are the wrong pins to use. Any suggestions would be appreciated.[

Added: just for reference the I am using Molex C-grid pins for the underside connections, #0015910080 , digikey pnWM17458-ND

Thanks
Mike

ATTACH=CONFIG]8726[/ATTACH]

UPDATE: Ordered a new batch from pcbway.com (china), got these for 5 for $27 which is $5.40 for just the board. Will try others if I do another version. Still can not get the under pins aligned.
 

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Got a new design. Any comments would be appreciated.

Teensy_Uno.jpg

Here is a photo of the assembled board. Partially tested - have a couple of connection issues but it works.

20161117_135910.jpg
 
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Hi All

Need some help. Having a devil of a time getting reset and pgm working. Right now I have 3.3v going to the resistors then to the switches. When connected the board is not recognized as a serial port - I can load a sketch no problem. If I cut the power to the resistors all works fine. Next test is the battery.

Mike

--------------------------------------
Update. Ok. Me bad - had to connect it to ground. Do I really need the resistors? Otherwise so far everything seems to be working.
 
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SWD Debugging the Teensy 3.5 and 3.6

Paul mentioned a proper way for debugging, integrated into the Arduino IDE, is on his to-do list. Maybe this will use JTAG as well?

According to Pauls quote in https://forum.pjrc.com/threads/42728-Debugging-strategies, this is *still* not supported.
What I ended up is removing the the KL02Z on the Teensy so I can use normal Eclipse, GDB and JTAG (actually SWD) debugging tools:
https://mcuoneclipse.com/2017/04/29/modifying-the-teensy-3-5-and-3-6-for-arm-swd-debugging/
kl02z-removed-from-teensy.png

What you need are wires, low soldering skills and a hot air gun for taking off the KL02Z.

I hope this helps,
Erich
 
Teensy 3.5 in a Arduino Mega Footprint

Know this is an old post and there are some breakout boards already available but based on a post by @MichaelMeissner decided to design a teensy 3.5 and put it into a Arduino mega type footprint. I used the power design from the mega to save some time. The attached photo is for reference. Got blink working on external power and usb powered. Found a couple connections that were not made for some reason, so used jumpers for now. Want to do some testing to make sure the other connections work as well. Does any one know of an easy way to do type of testing?

Thanks
Mike

20170508_221235.png
 
Back when we were doing lots of widget development on T3.1s then 3.2s, built a simple 'loop-back' board that had headers for directly-mounted teensy, or could be pressed onto the test header of our widget. Very simple - several I/O to control analog muxes in cross-point config, then just had all of the analog channels read all of digital pins, and used some pins to generate interrupts in other pins, then read an external ref V into analog I/O. Test took under 15 sec then burned an unique ID into EEPROM, which became the widget's serial.

If feeling froggy, look at all of the stuff (including PhD papers) on boundary test and other such test automation. Also use to verify the teensy module when it comes back from the field.
 
For the fun of it, I thought I would play around with newer beta version of Diptrace and update my RPI shield for the T3.6, to make it small enough to fit without overhanging the USB connections on the front...

Currently it is looking like:
T3.6-RPI-Hat-V2.jpg

Currently I have it powered by a pololu DC/DC converter, but also would like at least portions of the board to be able to be powered by USB.
Currently I have it setup to have a diode between VIN/VUSB, but wondering about other power issues.

In particular, if I am powered only by USB, I don't want the board to feed the +5v to the Host connector pins. Probably the rest of the board would be fine to be powered by USB...

Suggestions? Use another Diode between the USB and the +5v going to the host?

Recommendation for which Diodes you like using?

Thanks
Kurt
 
In particular, if I am powered only by USB, I don't want the board to feed the +5v to the Host connector pins.
You may know, but the 5V pin is connected to the TPD3S014 power switch and it's off by default.
 
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Recommendation for which Diodes you like using?
In similar situations we use a Schottky such as Central Semi CMSH2-40L TR13, less than 400 mV Vf at 2A, lower Vf at lower currents. We typically need less than 1A operating current when we use this part. Digikey has them, about $.45 @1000. If you want a few (like 10-20 or whatever) I can give you some via USPS 1st class, msg me your address; we have a reel on hand.

Actually from Future it looks like we paid under $0.17 each for a reel.

We use these to prevent USB back-driving other power supplies or boards, and also as part of reverse-voltage protection on board inputs (this schottky and then a zener such as 5V SM5908. We use a somewhat wimpy trace to the protection circuit so that if there is a bad power connection the trace actually acts as a fuse and blows. It happens on maybe 1/1000 boards we ship, but it usually does save the board electronics from damage. The blown trace can be repaired with a short length of 30 AWG wire wrap wire which can easily carry 1A.
 
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I have my Mega type board working with the Teensy 3.5. Still checking of course but tried a couple of shields with the board, USB Host Shield, adafruit motor shield and a DF robot io shield for the mega. So, I decided to try and make a Arduino size shield for the Prop Shield:

Capture.PNG

One of things I decided to do in the revision of the my mega board is to bring DAC0 to the NC pin of the mega shield so it is available for this shield. The one question I have is the 5V power on the audio and LED pins. Are they output pins from Vin from the Teensy or are they separate power pins or are they both? do I need diodes if the later is the case.

Of course any suggestions would be helpful.

Thanks
Mike
 
@bboyes: Thanks, I ordered some schottky diodes from digikey along with some other parts I needed, which arrived yesterday.... So soon will try assembling one...

@mjs513: looks like fun! My guess for power is... It depends. If you are going to run a lot of LEDS, I would use separate power. But if you are only going to run one or a few on the board, you could probably use VIN. Sound, probably again depends on what you are going to hookup. As for diode... My board above I added two diodes, one to not back power the USB and another to only power certain things when external power is connected (i.e. don't try to power an RPI or the like from the USB input)... Others who are less electrically challenged than myself can probably give better answers :D
 
Thanks for getting back to me Kurt. Think I will add one of the pololu step-up/step-down regulators for the external power source and put the diodes between Vin and the +5V power pins for the leds/audio just in case I want to do more than power a small speaker. Any suggestions on the type and size diodes. I usually use 1N4001's but something tells me I may need a different one. These boards are my first foray into designing my own so I am working by the seat of pants :).
 
Thanks Kurt. Got it redesigned but am going to hold off on shooting the order off. I'll wait and see if there are any other thoughts out there.

Thanks again
Mike
 
Thanks Kurt. Got it redesigned but am going to hold off on shooting the order off. I'll wait and see if there are any other thoughts out there.

Thanks again
Mike

Schottky diodes have a lot less forward drop, so less wasted power in the diode. They cost a bit more is the only real downside. You can also use FETs to switch multiple power sources and allow only one, but that gets more complicated (so you'd need a proper design for each specific application) and expensive than Schottky diodes. However the voltage drop on a FET can be super low, but you pay more $$$ for that. Schottkys are easy to apply.
 
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