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Thread: Teensy LC MKL26Z64

  1. #1
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    Teensy LC MKL26Z64

    Hi all,
    I am struggling to find the documentation that I need regarding the subject microcontroller. I have a fair amount of experience with other micros so it appears to me that this one is sorely lacking in documentation relative to what I have come to expect, and what there is doesn't seem to be well written. For example, in datasheet # KL26P64M48SF5 the term "POR" is used in one of the tables but is not defined anywhere. Now I know of course that "POR" is "Power On Reset", but if I didn't already have that knowledge where would I find it in the MKL data? There just seems to be a lot missing, including some things that I am looking for, specifically:

    1> There must be a programming guide for the part somewhere that would include details related to where the processor starts after a POR event.

    2> Page 7 (Table 6) of the datasheet references low voltage warning thresholds. This is extremely important to me because that term (and the datasheet itself) implies that there are eight different thresholds that the micro may be monitoring that may allow me to detect a falling battery voltage condition without having to install a separate supervisor chip. And assuming that there are indeed eight different programmable thresholds then how do I select the one (or ones) that I want?

    So to sum it up, I would appreciate it if someone could point me in the direction of the documentation that I'm looking for, and if you might have the answers to my two questions I would appreciate that too!

    Thank you in advance,
    Ray Russell
    Houston, TX

  2. #2
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    Quote Originally Posted by SBI Inc View Post
    Hi all,
    I am struggling to find the documentation that I need regarding the subject microcontroller. I have a fair amount of experience with other micros so it appears to me that this one is sorely lacking in documentation relative to what I have come to expect, and what there is doesn't seem to be well written. For example, in datasheet # KL26P64M48SF5 the term "POR" is used in one of the tables but is not defined anywhere. Now I know of course that "POR" is "Power On Reset", but if I didn't already have that knowledge where would I find it in the MKL data? There just seems to be a lot missing, including some things that I am looking for, specifically:

    1> There must be a programming guide for the part somewhere that would include details related to where the processor starts after a POR event.

    2> Page 7 (Table 6) of the datasheet references low voltage warning thresholds. This is extremely important to me because that term (and the datasheet itself) implies that there are eight different thresholds that the micro may be monitoring that may allow me to detect a falling battery voltage condition without having to install a separate supervisor chip. And assuming that there are indeed eight different programmable thresholds then how do I select the one (or ones) that I want?

    So to sum it up, I would appreciate it if someone could point me in the direction of the documentation that I'm looking for, and if you might have the answers to my two questions I would appreciate that too!

    Thank you in advance,
    Ray Russell
    Houston, TX

    Update: On a whim I Googled "MKL26Z64 SDK" and found what looks like some of what I'm looking for--I haven't gotten into it yet but it does look hopeful. Why it doesn't seem to be "connected" to the datasheet is beyond me...

  3. #3
    Senior Member+ KurtE's Avatar
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    I assume you looked at both Datasheets for the Teensy LC that are referenced at: https://www.pjrc.com/teensy/datasheets.html

    For most of the Teensy boards, I know Paul would suggest looking in the book mentioned on that page as well: Definitive Guide to ARM Cortex-M3 & Cortex-M4

    As the LC is an M0+ not sure if he would recommend also getting the book: The Definitive Guide to the ARM® Cortex®-M0 and Cortex-M0+ Processors, Second Edition

  4. #4
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    Thank you Kurt for your kind reply. The answer to your suggestion is that no, I haven't. I am very new to this site, having really been primarily interested in the uC itself. I happened upon the Teensy LC board, which is perfect for my application, and which saved me the aggravation of breadboarding it. I was treating the uC like I have all of the others I've used in the past, which basically just using the manufacturer's literature. But having just gone out to the "datasheets" page that you suggested I can see that what I was looking for is indeed there. I just wish that NXP had made it as easy to find as this site has.

    Thank you again

  5. #5
    Senior Member PaulStoffregen's Avatar
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    NXP/Freescale publishes 2 documents for each chip. The "datasheet" has the electrical specs. The "reference manual" has documentation about how the chip actually works.

    The ARM processor is only minimally documented even in the reference manual. Follow Kurt's link to the "Definitive Guide..." book. That info is also available directly from ARM, but it's quite difficult to read. If you want to go down that path, the magic word to google is "DDI0403E".

  6. #6
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    Thank you Paul.

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