Teensy 3.5 -- program without USB?

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jwatte

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Is it possible to program the Teensy 3.5 using some tool other than USB?
For example, JTAG? Or does Kinesis have something similar to ST-Link for the STM4 processors?
I want to use a Teensy as a part of a bigger system, and support in-system reprogramming, but I don't have USB.
(I have other logic and wireless communications though)
 
USB is the only supported way.

There are other unsupported ways, all with significant limitations and drawbacks. They've been discussed on this forum. Did I mention they're unsupported?
 
I see. I Googled around, and didn't really find anyone who actually had reported success with either JTAG or SWD.
Is there some post where such has been discussed you're aware of?
Given how the Teensy "dynamic duo" approach leaves the original MCU in a pristine state, it would seem like, if I could get SWD going, it would be doable without all that many caveats? (I'm still using a Teensy-built hex image and such, so the main concern is getting it into the flash.)
 
The successes have been around either pulling a hex file from an SD card or by serial. Not aware of anybody doing it properly via JTAG or SWD. Though that said if you have access to such tools can't you just use the Teensy built hex file as is and skip the bootloader IC?

The search term is 'OTA updates' and there have been a couple of people report success for their specific use case, though some didn't post code as far as I know. See also http://www.utasker.com/kinetis/TEENSY_3.1.html for a commercial route, though unsure if they updated to 3.5/6.
 
can't you just use the Teensy built hex file as is and skip the bootloader IC?

I guess that's what my question is. Are the necessary SWD connections all available? And, more importantly, does the DE pin going low now tri-state the secondary bootloader MCU? I thought there was some conflict there when I scanned the forums threads.

UART (serial) would be event better for me, because I don't particularly relish learning and developing a SWD interface for the other board in this system to drive the Teensy...

Thanks for the pointer, I'll search for "OTA update" and see what comes out.
 
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