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New Wroom-32 modules JTAG Problem

Posted: Tue Jan 23, 2018 3:59 pm
by rKirstein
Hi, I'm currently working on a project with the Wroom-32 module.
In the current batch of modules we bought, i think from mouser, the preinstalled image is using the JTAG pins and the module won't answer to any JTAG requests without being reset.
I Tweaked around on the openocd script to reset the module via the EN pin, but this only allows for erasing the installed firmware. After that i can use it normally without any tweaks in the openocd script.
I was unable to create a openocd script that allows for programming and debugging with the reset being used.
We had the same behavior on at least 10 modules from the same source. I believe the first batch we had did not have any problems like that.
Is there anyone familiar enough with openocd to create a script that uses reset and works for debugging? or is that impossible?
Are all Wroom-32 modules preprogrammed? or did we just get a bad batch?
Rico Kirstein

Re: New Wroom-32 modules JTAG Problem

Posted: Wed Aug 29, 2018 6:08 pm
by Sunil Dullolli
It seems like even I am facing the same issue. I got few new ESP-WROOM-32d modules which don't respond to any JTAG requests. I am able to program/debug the WROOM module in ESP-EVB launchpad with help of JTAG but I am not sure why same thing doesn't work on new modules. Even I have a feeling that modules have pre-installed image that use JTAG pins.

@rKirstein, how did you reset the module via EN pin (what changes do I need to make in OpenOCD script)? What are the things to look at? How did you overcome this issue?

Thank you in advance.

Re: New Wroom-32 modules JTAG Problem

Posted: Fri Oct 19, 2018 10:53 am
by ESP_Lvxinyue
It seems like the initial firmware is interfering with JTAG pins.

Do you know what is the firmware flashed onto these new modules at factory, and why does it use JTAG pins?

Re: New Wroom-32 modules JTAG Problem

Posted: Sat Dec 14, 2019 1:14 am
by lotharyx
Bump. I've just encountered apparently the same issue. I can probe the four pins with my scope and see that "TDI" is pegged at ground.
rKirstein wrote: I Tweaked around on the openocd script to reset the module via the EN pin
Could you explain exactly what you did to accomplish this? I'm not familiar enough with the guts of OpenOCD in order to pull this sort of trickery.

I'd at least like to see SOME response on the TDI pin, even if it doesn't get me as far as actual debugging...