Teensy 3.2

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Constantin said:
That's really nifty. I couldn't see a pricing sheet there, could you give me a ballpark re: cost? Perhaps normalized across a typical set of boards on a $/in^2 basis, for example?
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I think you really need to get a quote. They are more than willing to do that. The last couple I had done were paid by my clients and I'd be guessing but I'm thinking maybe $500 to get set up. I can't get a screen printer set up at a contract manufacturer for twice that much less get any panels printed.

Because there is the cost of making a stainless steel stencil and set-up, there is going to be a minimum charge. Then there is a cost per panel to do the actual process which is heavily dependent on volume so the setup is amortized over multiple boards.

Like most volume processes, it is less expensive to do multiple boards per panel because most of the charge is based per stencil wipe. If I recall, they probably use a standard squeegee that will probably print a panel about 17" wide but you should confirm that. So they can probably print about 17" square and a panel that is less will cost essentially the same amount, so it pays to use big panels and then break them apart.
 
Thanks everybody for the feedback.

veng1 said:
There are two variables, the stencil thickness and the pad reduction. I tend to use a thick stencil because I want the largest components I can get away with.
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Can you share your pad reduction parameters or are they a trade secret :) ?

Thanks,
_Markk
 
There aren't so much trade secrets as experience with the target production process. If you are going to a contract manufacturer, the easiest thing is to ask them the size boards they want to process. And their preferred stencil thickness. I've tended to err on the side of too much solder because I wanted to make sure I had maximum heat transfer but 3-6 mils, probably on the lower side. Typically the maximum placement area is 18" X 18 " although very few houses will work with boards that big. Because needed to process large LED display panels, I had two machines back to back with offset board stops to handle 24" boards. Also ask the board house for the edge clearance because there is a limit to how close components can be put to the sides of the boards and miss the conveyors. After you know what is a suitable board size, send the Gerbers to the PCB manufacturer. If you know what panel size you want, tell them or say something like:

Panelize the attached Gerbers for maximum yield with a panel size not to exceed ?? X ?? inches.
Send full size Gerbers back as panelized for making a solder paste stencil.

Then send the Gerbers for the panel to the stencil house and tell them:

Please use the attached Gerbers for a ?? mil thick stainless steel stencil to fit a standard 26" X 26" frame (or whatever size the contract manufacturer needs)
Reduce all pads by 10%.
Perform tombstone reduction on all 2 pad components such as R's and C's. (also whatever size the contract manufacturer needs)
Windowpane all large thermal pads.

Then when you get the boards back, inspect the solder joints with a magnifier and decide if the fillets look good. I'm sure there are pictures that can be found with Google to show good fillets or but the better practice is to use a copy of IPC-610. In any event, the fillets should be concave, not convex.

After that, you just keep doing it until it's good enough.
 
IIRC, The boot loader chip powers down unless you press the prog button to erase the teensy mk20 flash to prepare it for a new upload. Only the first few beta test boards featured a non sleeping mkl02.

Can that chip be removed? Sure, I did that with one of the LC's when I needed to harvest a MKL-02 before they were released as standalone chips. However, you risk damaging the rest of the board and likely will damage the MKL02 as well. MCUs can only handle so many heating cycles before they become less reliable. FWIW, my recycled MKL02 worked. I heated it with a hot air gun followed by rapping the board on a hard surface causing the chip to fly off. I then fluxed the daylights out the thing and used braid and a spotless, tinned tip to clean up the contacts.

Now that MKL02 chips are available, I don't see the benefit of harvesting old chips. Too much risk, too little return, unless your time is free, enthusiasm is high, and you don't mind the potential issues associated with a fried MKL02.
 
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Hi all,

can I remove bootloader after once burned the program, as I have to run a single program and don't need any changes.
And also, any separate bootloader is available so that I can reconnect and burn the program.
 
There is no bootloader stored in flash to remove. The Teensy scheme uses a stand alone programming chip on the board that facilitates the programming.
 
Yes you can remove it after flashing. However, before you go down that path, I suggest you read up on the issues associated with that on store page for the chip.

Bottom line: if removing the boot loading chip is what makes the difference between a potentially profitable design and a loss-maker (at the pilot production stage) then your product needs to be rethought. You are much better off in the first generations of alpha and beta testing to be able to quickly reprogram your boards. If your design makes it into high volume production, it may make most sense to preprogram the MCUs in a rig or the board as a whole (as Paul does).

I toyed with the idea of external programming boards but then reconsidered. For one, it complicates programming, introducing more failure points. Secondly, there is the issue of how to support Paul and his efforts. It's much easier from an accounting point of view to simply include the boot loader chip and be done with it. If you want amazing tech support, you have to pay for it.
 
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Id have to second Constantin. My product with the MKL02 in it here:
https://windfreaktech.com/product/microwave-signal-generator-synthhd/
I put the hooks to remove the chip and have ISP programming, but so far have been building with the MKL02. Im not even really planning to remove it. We sell a few to Universities so it probably just helps my bottom line to give people the power to be "Aurduino Compatible" and "easily" program their own firmware.
A big BUT.. But my BOM and selling price are high compared to the price of Paul's chip which helps out a bunch. Obviously, if you are going for low ASP and volume you might want to remove it quickly.
 
Paul said:
Today we're happy to release Teensy 3.2.

http://www.pjrc.com/store/teensy32.html

Version 3.2 is a minor upgrade to Teensy 3.1. The main change is an improved 3.3V regulator, to allow Teensy to directly power ESP8266 Wifi, WIZ820io (W5200) Ethernet, and other power-hungry 3.3V devices.

We're specifying Teensy 3.2's power output at 250 mA and the maximum voltage input at 6 volts, due to PCB thermal dissipation limits. However, the actual regulator chip is capable of up to 10 volts input, and up to 500 mA output. These higher limits are intended to allow Teensy 3.2 to be more rugged when used with non-USB power sources which aren't well regulated 5 volt sources.

Teensy 3.2 is fully compatible with all shields and add-on boards designed for Teensy 3.1. It preserves the same size, pinout, and processor as Teensy 3.1.

The bootloader chip is also changed from Mini54 to KL02 (the same as Teensy-LC). A full schematic is available:

http://www.pjrc.com/teensy/schematic.html
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hi Paul,

i just received my teensy 3.2. i am a new bee with this board and i want to design my custom teensy3.2 board.
i will use your schematic to do this but i wonder that after installing all the component,
is there any need to upload firmware into the main processor and/or KL02 to program the processor with the arduino IDE.
 
The KL02 is needed every time you want to upload firmware. It is a hardware replacement for the boot loader which "eats", when realized in software, a part of the processor's flash memory, like it happens for the Arduino boards. The KL02 does handle the boot loading thing, and the whole flash memory of the Teensy is free for your programs.
 
fenestron said:
is there any need to upload firmware into the main processor and/or KL02 to program the processor with the arduino IDE.
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The MKL02 can not be programmed by yourself if you want to use the teensyduino ecosystem, it's firmware is a trade secret of PJRC. You can buy pre-programmed MKL02 ICs directly from PJRC: https://www.pjrc.com/store/ic_mkl02.html
On this page you'll also find useful information for designing your own board.
 
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