Use NC pins on WROOM and WROVER to relay power?

zliudr
Posts: 171
Joined: Thu Oct 03, 2019 5:15 am

Use NC pins on WROOM and WROVER to relay power?

Postby zliudr » Mon Nov 18, 2019 2:01 am

Here is an NC on the WROOM module and 3 NC's on the WROVER module. From the schematics these pins are not connected to any pins on the modules' PCBs, correct? So if I want, I can use them to route 3.3V from one side of the module to the other side by connecting VDD/3V3 to NC, instead of routing around the module, right? Thanks.

WiFive
Posts: 2952
Joined: Tue Dec 01, 2015 7:35 am

Re: Use NC pins on WROOM and WROVER to relay power?

Postby WiFive » Mon Nov 18, 2019 2:54 am

Seems like a clever design. You can check the Gerber files in the reference designs https://docs.espressif.com/projects/esp ... reference/ to make sure the pads are isolated.

boarchuz
Posts: 257
Joined: Tue Aug 21, 2018 5:28 am

Re: Use NC pins on WROOM and WROVER to relay power?

Postby boarchuz » Mon Nov 18, 2019 3:16 am

Incidentally, I just had some PCBs delivered 5 minutes ago where I've done something similar on a little 2-layer board.

What I did was to edit a custom WROOM footprint where I've removed the pad entirely (ie. There's soldermask where that pin will be on the WROOM, so it won't be soldered to the board at all).

zliudr
Posts: 171
Joined: Thu Oct 03, 2019 5:15 am

Re: Use NC pins on WROOM and WROVER to relay power?

Postby zliudr » Mon Nov 18, 2019 6:16 am

WiFive wrote:
Mon Nov 18, 2019 2:54 am
Seems like a clever design. You can check the Gerber files in the reference designs https://docs.espressif.com/projects/esp ... reference/ to make sure the pads are isolated.
Thanks. The reference link is broken. Following your link's address I found this one that works:

https://www.espressif.com/en/support/do ... nce+Design

Those pads are 7th from top right and 8th and 9th from bottom right. They are not connected to anything :)

zliudr
Posts: 171
Joined: Thu Oct 03, 2019 5:15 am

Re: Use NC pins on WROOM and WROVER to relay power?

Postby zliudr » Mon Nov 18, 2019 6:22 am

boarchuz wrote:
Mon Nov 18, 2019 3:16 am
Incidentally, I just had some PCBs delivered 5 minutes ago where I've done something similar on a little 2-layer board.

What I did was to edit a custom WROOM footprint where I've removed the pad entirely (ie. There's soldermask where that pin will be on the WROOM, so it won't be soldered to the board at all).

What I did a while back was to rearrange the bottom pads of a WROOM footprint to make my own WROVER footprint. Back then I couldn't find WROVER EAGLE parts library. I guess it should be easier to find them now. I still want to keep consistency among my "technologies" so I'm not deleting the pads. Plus, symmetric is best for reflow and strength. In my pin usage document, I've marked off the NC pins as used on psram so I won't use them on WROOM by accident and can't migrate to a WROVER ;)

I find the WROVER design better for routing since the once closed off bottom edge is now open and I can now route through this side.

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