Test Points

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loglow

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Hi,

Please forgive me if this has already been documented or discussed somewhere, but I couldn't find it...

What are the following 4 unmarked test point signals used for?

teensy32tp.jpg

Thanks very much! -Dan
 
Similar question to the above, but now for the Teensy 3.5 & 3.6:

What are these two test point signals (circled in red)?

36tp.png

Thanks!
 
Same idea. The MKL02 bootloader likely gets programmed using those points.

That way, PJRC avoids having to unreel/program/re-reel MKL02 chips before sending them to the assembly fab for installation.

Instead, the fab sources 'virgin' MKL02's and reflows onto the board. After delivery to PJRC, Pauls bed of nails torture rig not only tests each board but also flashes the MKL02 chip.
 
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Constantin said:
Same idea. The MKL02 bootloader likely gets programmed using those points.
Click to expand...

Cool, and thanks very much for that info.

When you say "same idea" do you mean that they're likely SWDIO and SWCLK (SWD interface) like on the Teensy 3.2? (the other T3.2 test points being USBID, RESET, and VDDA)

I don't know much about the SWD interface (or JTAG for that matter) and I didn't realize that it could be used to program chips like this. Can it?

Can anyone confirm or verify this? And also, which pin is which?

(I'm also assuming that T3.5/T3.6 schematics haven't been released yet, is that right?)
 
If you follow the traces on the pcb, they go to pin 14 and 16 from the KL02.

In the picture above:
left test point is pin 16/PTA2/SWD_DIO
right test point is pin 14/PTA0/SWD_CLK

If the KL02 chip is not write protected it can be programmed with the SWD interface. The KL02 chip stores the bootloader, if you program the KL02 with your own code, it'll destroy the bootloader function. It is not recommended to program the KL02 using the SWD interface.
 
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Indeed, don't mess with those test points. The protocol is very complex, so the odds of doing anything by mistake are slim. But if you do, the only likely outcome is bricking your Teensy. Don't do that.
 
HWGuy said:
If you follow the traces on the pcb, they go to pin 14 and 16 from the KL02.

In the picture above:
left test point is pin 16/PTA2/SWD_DIO
right test point is pin 14/PTA0/SWD_CLK

If the KL02 chip is not write protected it can be programmed with the SWD interface. The KL02 chip stores the bootloader, if you program the KL02 with your own code, it'll destroy the bootloader function. It is not recommended to program the KL02 using the SWD interface.
Click to expand...

Thanks very much!
 
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