Reliable way to obtain the MPN or Ordering Code of a module

[tosemusername]

How do I reliably obtain the Ordering Code or Manufacturer Part Number for my particular module? The closest way I've found so far is by running esptool chip-id, but it seems to be missing information about the PSRAM of my vanilla ESP32.

Screenshot From 2025-10-04 22-18-10.png (12.7 KiB) Viewed 1614 times

[Sprite]

I don't think you can read that using software. You can usually (in newer modules) derive it from the inscription of the module shield, though.

[tosemusername]

You can usually (in newer modules) derive it from the inscription of the module shield, though.

I figured as much from here
https://docs.espressif.com/projects/esp ... index.html

But does that mean I can't reliably determine how much PSRAM my module has?

[Sprite]

I figured as much from here
https://docs.espressif.com/projects/esp ... index.html

But does that mean I can't reliably determine how much PSRAM my module has?

You can. If you look at the specification identifier, it looks like ??NxRy??, with x being the flash size and y being the psram size, in megabytes.

[tosemusername]

Any idea how to read this?

20251007_115648.jpg (1.07 MiB) Viewed 1574 times

[Sprite]

Hm, you're right, I guess the shields on the Wrover still follow the old format. Well, the good thing is that you can still find it: simply grab any ESP-IDF (or Arduino project, I think), enable PSRAM and the startup chatter should have a line that tells you how much PSRAM it detected.