ESP-WROOM32 + PSRAM

[ttc7152]

Hi all,

We are developing a product using the ESP32 based modules, and have arrived at a fork in the road in terms of which module to use.

We've been using the WROVER as we liked the uFL connector option, however we are now aware the WROOM32 will have a uFL version as well. Secondarily, the extra 4MB PSRAM on the WROVER makes this attractive as we will have flexibility down the road in developing firmware features that may require the extra RAM.

The dilemma is the WROVER is not IC (Canada) certified but the WROOM32 is. We are checking on the feasibility of IC certification, and this is certainly an option, however we are not sure if we would be able to obtain modular certification. If we used the WROVER in multiple products, it would be nice to have the modular certification.

So the big question is whether we can easily add PSRAM separately to the WROOM32?? It appears the ESP-PSRAM32 is 1.8V and the WROOM32 flash is 3.3V, and the pins are shared. We also notice the MTDI can be set to high which appears to set the voltage? But we also cannot find examples of anyone doing this on the forums. Perhaps we are overlooking something obvious here. Also we've noted the WROVER flash and PSRAM are at 1.8V.

This lengthy thread discusses a different brand of PSRAM which doesn't seem to work quite right:
viewtopic.php?f=13&t=2031&hilit=adding+ ... 2&start=30

This thread discusses a custom design using the ESP32 but of course this is not certified at all:
viewtopic.php?f=17&t=2227&p=18840&hilit=psram#p18840

Thank you in advance for the help on this ...

Ted

[p-rimes]

That is so interesting! I had only been looking at the FCC registrations so I had assumed WROVER was listed in IC as well. Maybe Espressif can comment if that certification is something that is pending?

Otherwise, I am a bit worried and in the same situation (e.g. needing workarounds to upgrade the WROOM module)

[WiFive]

IC should just be a filing fee and paperwork on top of FCC so it seems like an oversight. But actually none of them are certified with external antenna yet anyway. Only esp8266 wroom-02u has fcc but not IC.

[ttc7152]

I'm hearing the WROOM-32 uFL version will be fully certified like the WROOM-32 (FCC, IC, CE, and more) ...

Also I've heard that Espressif won't be pursuing IC on the WROVER although I'm wondering if its possible to convince them.

Would love to hear if anyone has added PSRAM to WROOM-32 module.