New bootloader chip Eagle libraries

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Constantin

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Ladies and Gentlemen,
I continue to be stuck in the Midwest thanks to airline mishaps and took the time to expand the Eagle libraries for the bootloader chips that PJRC is offering and / or will be offering in the future. Specifically, I added the 5x5mm QFN-33 package for the Minitan54, as well as attempted to figure out what Mr. Stoffregen did to bless the LC with a even smaller bootloader chip than the Minitan54 that is meant for the Teensy 3.0 as well as the Teensy 3.1.

However, seeing that there is no schematic yet (as of this writing) describing the connections between the bootloader and the MKL26Z MCU that makes up the LC, all I could do was study the posted images very carefully and try to deduce the connections. As best as I can tell, the fine folk at PJRC are programming the bootloader MCU at PJRC (great idea!) once the LC board has been assembled. Only then, can the bootloader commandeer and help program the LC MCU using the SWD protocol. (At least this is what I think happens. Caveat emptor, I am a Mechie.)

Teensy LC Bootloader.png

So the above image shows what I think the connections are on the Teensy LC bootloader chip. Before I post libraries, I would like Mr. Stoffregen to weigh in on whether the connections look correct (once a schematic is posted, I'm happy to do that also). Please note that PJRC does not plan to ship the bootloader chips for the Teensy LC series for a while yet (several months). I simply had some time and thought it would be a fun puzzle.

Teensy 3.x bootloader.png

I also worked on creating a QFN-33 package for the Minitan54. I picked a QFN-33 package from the ON Semiconductor library and made the connections per the data on the MiniTan54 sales page. I wonder if someone could double-check my work re: the port assignments for the Minitan54 and the connections to the MK20DX MCU that powers the Teensy 3.x series. The official pin assignments can be found here.

If the pin assignments and designations seem to make sense, please let me know. I'll post the updated bootloader libraries at that point. Since the 4x4mm QFN package is very similar to the 5x5mm package (save for the exterior dimensions), adding that should be pretty simple once the pin assignments have been confirmed.

EDIT: Past drawings / symbols above for the LC bootloader reflect an error in Pauls originally-posted schematic for the LC that have since been corrected. Pin 10 is attached to the tactile PGM switch, not pin 11, as originally shown.
 
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Oh, I forgot to mention that pin 2 and 17 (pad) are GND for the KL02 bootloader chip for the LC series.

On the MiniTan54 in its QFN-33 version, pins 12, 17, 32, and 33 (pad) are attached to GND.

It's pretty striking just how tiny the KL02 bootloader chip is compared to the Minitan54 (3x3mm vs. 5x5mm for the QFN or 10x10mm for the LQFP).
 
Hi everyone,

I revised the boot loader chip and the connections on the MK26 based on Pauls schematic:
schematic_lc.gif


The attached library contains the legacy as well as current bootloading chips. The MKL02Z/MKL04Z are the current generation of chips for the Teensy 3 and LC series while the MiniTAN54 is also included for legacy reasons. Also attached are all MCU footprints in the Teensy 3 and LC series.
 

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OK, as has been reported elsewhere, the previously posted schematic for the LC had an error in it. The drawing above shows the correct pin (10) being attached to PGM, while the previous schematic references pin 11, as seen below.
attachment.php

I have since updated the LC files for the bootloader chip to reflect reality. The new library has the correct pin assignments for both the LC bootloader as well as two out of three Mini54 bootloaders for the Teensy 3.x series. I have not created a QFN 4x4mm version yet, as I doubt that I'll ever try to solder that up. A 0.4mm pin pitch is pretty evil to work with without some big magnification and very good gear. My LC seems to work despite some strange pin voltages that I've encountered.
 

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  • Teensy_DIY_v1.0.zip
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Hey Paul, would you consider pointing a link to this page so folk can get the Eagle files for three of the four boot loader chips?
 
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