T2M, an Embeddable Teensy Module (WIP)

[loglow]

Do you have a mechanical drawing or some dimensions for a footprint?

Here are some some board and footprint drawings of the current design (units are mm):

Also, what's the timeframe for a beta?

Timeframe for a beta is probably 6-8 weeks. The current revision is going to start being assembled in about one week, and should be done in a few more. Then it has to be shipped to me and finally I get to test it out.

Also, you might notice that the castellations are a bit larger than before. This is because the PCB fab house has a minimum size of 0.6 mm for castellated holes. Fortunately, that still works for this design, it just needed some tweaking.



I'm keeping the suggested footprint the same as before so it's still possible to route between the pads using reasonable trace/space width (6/6 mil) with a little room to spare (there's about 20 mil between pads).



By the way, the specs on the T2M board itself are: 0.8 mm thick, 4/4 spacing, 0.2 mm drills.

[loglow]

This is great!
I've often thought about this sort of thing as much as I love the teensy's, I really don't care for 0.1" header as I'm almost always dropping them on a PCB. Personally I'd want a bootloader and a USB because most of my work requires a USB for comms, but you can leave these off the module. Anyone who can use this module should be happy enough to add the bootloader/USB themselves, and actually I also like having the choice of connector to suit the application. I'm also 100% on board (yes, pun intended) with castellations, as previously said because you can reflow them or use an Iron. You also get the bonus of easily visually inspecting the solder to check it's good, which those of us using hacked toaster ovens for reflow (or is that just me?) value.
Talk to us about beta!

Thanks! I'm inclined to agree with you, except that I've really come around to the option of having the bootloader on-board. Obviously this variant won't actually be available for a while, until the PJRC bootloader is released. But in the meantime, the bootloader-less variant will be available. I really do hope the LPC-Link2 works out. I was looking at Segger J-Links the other day but I haven't picked one up.

These are gonna be difficult for some to hand-solder due to the small size, but certainly not impossible (1 mm pitch).

I use a toaster reflow oven too, with the Controleo2 kit. I've been meaning to grab their upgrade to a full color display, but I haven't gotten around to it. It works very well!

[loglow]

This looks really great, I will be keeping tabs on development. It seems like everything hinges on bootloader support to make it viable for production use.

Thanks! I hope it ends up being viable for production use with or without the PJRC bootloader! If the LPC-Link2 works out, then we're talking about a $20 programmer and a <$50 programming fixture.

[loglow]

Hi Loglow,

what a fantastic idea!
I was about to write a post asking the community for suggestions about the post-development phase, the one in which, after using the T4 for speeding up development, the time comes of putting the MiMXRT1062 on the final PCB.
In most cases, as in mine, for example, after the chip is put on the production-ready board, there is no need to flash the code using the Arduino IDE (or PlatformIO or whatever) anymore.
Is your design open-hardware or do you plan to sell them?
I'm certainly interested in the schematics, PCB layout and BOM. How many layers does your layout have?
In case you need a beta tester, I could even have a couple of your boards produced and provide feedback.
Let me know.

Yeah, I had the same thinking. Using the Teensy is great for development, and even for small runs of things, but it's not ideal to integrate into a product, due to space, headers, mounting, etc. And the BGA fanout makes dropping an RT1062 much more difficult than integrating an MK20 (Teensy 3.2) onto a PCB... needless to say, I'm not usually needing or wanting to pay for 4/4 tolerance with 0.2 mm vias on my end-use PCBs.

This design will be open hardware and I plan to sell them! I'm not sure about the license, but it'll be something permissive with attribution.

This is a 2-layer board, and the first time I've ever done BGA routing.

I'd love to have you beta test. Send me a PM if you'd like to discuss the possibility of manufacturing some on your end.

[blackketter]

If the LPC-Link2 works out, then we're talking about a $20 programmer and a <$50 programming fixture.

I meant to ask earlier, have you looked at the Segger J-Link debug probes? They are quite popular and have inexpensive models and claim to support the MIMXRT1062 here https://www.segger.com/downloads/supported-devices.php I'm particularly interested as they have solid support in PlatformIO.

[loglow]

I think this is a great idea and long overdue, I would buy them. If this ends up turning into a real board, I would think a teensy 3.2, 3.5/6 and an LC board would be a great idea also. A small, thin .8mm castellated teensy 3.2 / LC would be super handy for all kinds of things. Fist thing that comes to mind is thin small form factor LCD TFT backpack boards.

I agree, and I plan to make some (of the things you mentioned) if this project works out well. My previous take on that was this: https://forum.pjrc.com/threads/52751 but the form-factor was never really satisfying for me, it just wasn't small enough. At that time I deliberately made it so I could solder it myself, but now I'm much more comfortable with contract assembly and using minuscule components.

I'm starting with the Teensy 4.0 because a) it's so powerful, b) it's the latest and greatest Teensy, c) it has the difficulty of using a BGA-only chip, and d) it's nice and cheap! I might work backwards to the 3.2 next, but we'll see.

[loglow]

I meant to ask earlier, have you looked at the Segger J-Link debug probes? They are quite popular and have inexpensive models and claim to support the MIMXRT1062 here https://www.segger.com/downloads/supported-devices.php I'm particularly interested as they have solid support in PlatformIO.

Yeah, honestly they look great, but I was turned off by the fact that J-Flash software requires a J-Link PLUS at minimum, which is $600. I might pick up an EDU model to play with, but I'd be tempted to use it unethically and I'm not wild about that. The BASE is $200, still an order of magnitude more than the LPC-Link2.

[blackketter]

Yeah, honestly they look great, but I was turned off by the fact that J-Flash software requires a J-Link PLUS at minimum, which is $600. I might pick up an EDU model to play with, but I'd be tempted to use it unethically and I'm not wild about that. The BASE is $200, still an order of magnitude more than the LPC-Link2.

Gotcha. Poking around here https://www.nxp.com/design/microcont...-link2:OM13054 I see that the LPC-Link2 can load a Segger J-Link firmware. Might be the best of both worlds!

[loglow]

Gotcha. Poking around here https://www.nxp.com/design/microcont...-link2:OM13054 I see that the LPC-Link2 can load a Segger J-Link firmware. Might be the best of both worlds!

That's true! I think that gives it capabilities on par with the J-Link EDU/BASE, if I remember correctly what I read about it a few weeks ago (which I probably don't).

[wcalvert]

Bootloader update, Paul says he is working on the bootloader chip right now: https://forum.pjrc.com/threads/57132...For-Teensy-4-0

[wcalvert]

Hey loglow, in your pin listing on the previous page, is D1 USB device, and D2 USB host? I'm planning to start laying out a board revision just for this module.

[LenSamuelson]

Three years ago, I bought an Olimex FTDI-based JTAG programmer, a JTAG-SWD converter and a cable to match ARM's 10-pin footprint, with a total cost less than $100 (it could have been $50, I don't remember). OpenOCD 0.10.1 works well with it. The combination supports my day job of developing firmware for a Kinetis K60 based board and as of a week ago, a board with a K66 identical to the MCU used in the Teensy 3.6.

If anyone is interested, I can try to recall the specific parts we bought from Olimex.

[luni]

Wouldn't a Segger JLink mini work? You get it for $18 from Adafruit

[LenSamuelson]

The Segger unit would probably work, though it involves their software and more importantly to me, their licensing policies. When we were looking into debugger support hardware and software, one question we had was whether we could find a solution that doesn't require permission from a manufacturer to update our development systems.

We use a PEMicro unit in the hardware lab, and bought the Olimex unit to see how well it would work without the license tracking overhead.

[wcalvert]

Any beta updates?

[joey120373]

I really like the size, layout and the castellated pads, all good, I don't recall seeing a planned PCB thickness but hoping it will be .8 mm or less.

this is a great idea and cant wait to see the final product.

[pkrobot]

This is great, exactly what I was looking for. Can't wait for it to be released. I'll buy some..... Let me know if you need help with testing.

-pk

[defragster]

Here are some some board and footprint drawings of the current design (units are mm):
...

By the way, the specs on the T2M board itself are: 0.8 mm thick, 4/4 spacing, 0.2 mm drills.

Post #26 above ...

I really like the size, layout and the castellated pads, all good, I don't recall seeing a planned PCB thickness but hoping it will be .8 mm or less.

this is a great idea and cant wait to see the final product.

[pkrobot]

Any update on this?

-pk