Use MK22 instead of MK20

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Hello all,

We are designing a little product based on the MK20 and Teensy boards. We are currently purchasing bootloader ICs from PJRC and installing them onto our own boards.

We were getting ready to place a first bulk order but Digi-Key is out of stock of the MK20DX256VLH7 chips that are needed by Teensy system. It seems out of stock from most vendors for a month or two.

We were wondering about our options for moving forward asap.

I see that the MK22 variant, that happens to have more flash space, is available. I believe it is also pin compatible. (MK22FX512AVLH12 & MK22FN1M0AVLH12) How different could the peripherals be?

Does anyone know if the Teensy bootloader IC will work with the MK22 directly - even if it doesn't let us access all of the flash?

Is there any possibility of getting a version of the Teensy bootloader that does support the MK22?

If we can't use the Teensy bootloader IC, we do happen to have SWD available on the board and could possibly program like that. I wonder how much hardware initialization the Teensy bootloader software does and how specific it is to the MK20DX256VLH7. I wonder if we can just take a hex file from Teensyduino / platformio and load it onto the devices ourselves...

Thanks!
 
This is one area here where you will probably have to do some investigation yourself. Purchase a few samples of a pin compatible MK22 and transplant them onto Teensy 3.2 boards.

You may experience higher supply current (I bet you expected that). Being a former chip guy, semi fabs are out to improve yield and ROI ($$$) so they make use of partial good parts buy implementing laser or e-fuses and redundancy schemes to patch in or remove circuitry then sell the reduced capability chip at a different price scale. I have seen this done with memory (redundancy) and processors (core disconnection) .

Having gone thru some of the (quite extensive) MK20 and MK64 documentation myself, I recommend you embark upon that learning curve too to find the subtle differences between the two (MK20 vs MK22). Once you have some level of confidence the two are about the same then hit the lab and do some real world testing to see if the MK22 is use able with the boot loader. Perhaps if you talk (nicely) with Paul and/or Robin they might be willing to help you out with some samples to help move your project along.

Best of luck to you in your project.
 
Does anyone know if the Teensy bootloader IC will work with the MK22 directly

Very unlikely to work. But you could try anyway, if you're willing to lose a small handful of parts and several hours of your time to the experiment.

If you're going to need only a moderate number (dozens to low hundreds) of MK20 chips until NXP solves the shortages, and if you'll be pairing them with bootloader chips, contact Robin directly.


Is there any possibility of getting a version of the Teensy bootloader that does support the MK22?

No, sorry, not going to happen.
 
Very unlikely to work. But you could try anyway, if you're willing to lose a small handful of parts and several hours of your time to the experiment.
I did just this. We rushed some parts over from Digi-Key and I tried swapping out the MK20 with the MK22. While the Kinetis USB based bootloader did enumerate on my computer, pressing the reset did not make Teensy show up. I guess this was to be expected. (FWIW, I was able to do this on the first try without losing any parts :) It's handy to have a good hot air gun and soldering iron. To be fair, I do happen to do this type of rework all the time. Metcal definitely helps :)


No, sorry, not going to happen.
Figured. Worth asking :)

If you're going to need only a moderate number (dozens to low hundreds) of MK20 chips until NXP solves the shortages, and if you'll be pairing them with bootloader chips, contact Robin directly.
We need 20~25 parts asap. I believe we also recently ordered some bootloaders from you. How should I contact Robin?
 
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