how to access JTAG pins on ONE+ ?

User feedbacks of the latest ESP32 based Freematics ONE+
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aboaboit
Posts: 23
Joined: Mon Mar 26, 2018 4:55 am

how to access JTAG pins on ONE+ ?

Post by aboaboit »

Hi.

According to ESP32 docs, in order to use JTAG debug interfaces we need to access GPIO pins 12 to 15.
Is it technically possible to do so on the ONE+, hopefully via the XBee headers?

Thanks,
Andrea.

fwh
Posts: 4
Joined: Thu Sep 06, 2018 4:43 am

Re: how to access JTAG pins on ONE+ ?

Post by fwh »

If the pinout on this page, https://gojimmypi.blogspot.com/2017/03/ ... esp32.html, is correct, then when you open up your ONE+ you'll see that GPIO pin 12 is floating. It hasn't been soldered to a pad.

wyatt
Posts: 2
Joined: Tue Sep 04, 2018 12:56 pm

Re: how to access JTAG pins on ONE+ ?

Post by wyatt »

I have the same question. Any chance of using a USB debugger with GDB?

aboaboit
Posts: 23
Joined: Mon Mar 26, 2018 4:55 am

Re: how to access JTAG pins on ONE+ ?

Post by aboaboit »

After some studying of the schematics, I'd say this can't be done, period: pin IO15 is used to control GPS power (EN GPS1) so it's game over.
See https://freematics.com/dl/FreematicsONE ... ematic.pdf

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