ESP32-S3-MINI-1 with external PSRAM

[giacobbe_85]

Hello,

I would like to add an external PSRAM module to ESP32-S3-MINI-1, but I can't understand:
1) Which external PSRAM module, suitable for ESP32-S3, is commercially available?
2) The external ram is connected through SPI, but which pins should I connect?

Is there any example schematic around to copy from?

Thanks in advance

[djixon]

http://en.wireless-tag.com/product-item-15.html
that link contains a new WROVER-I design by Wireless Tag using ESP32 S3 chip version. (old WROVER uses ESP32 S2)
On that link you can download a pdf and see their schematic design. In general, external PSRAM and external FLASH both use the same SPI the only difference is CS (chip select) pin. Those are usually two different pins from ESP32, one is responsible for enabling the flash chip, while the other is responsible for enabling PSRAM.

[giacobbe_85]

Thank you for the nice find. Anyway, I was interested in specifically adding external psram to ESP32-S3-MINI-1. But in the ESP32-S3-MINI-1 schematic I see that the psram and flash SPI pins on the internal chip are not connected to the external module pins. I was hoping that other pins could be mapped in the ESP32-S3 to support psram. That is: connect psram to pins other than GPIO31, GPIO28, GPIO32, GPIO30, GPIO27.

[djixon]

It should be possible (of course, if you use pins for that purpose then you should avoid using them for other purposes).
In Technical Reference Manual, you can find SPI0 and SPI1 to which pins they can be remapped. Rest should be the same. Try to avoid using ANY strapping pin for your purpose.

[joergp]

@giacobbe_85 : did you find a solution for hooking up external PSRAM to the ESP32-S3 mini? Which pins have you used? I want to try the APS6404L-3SQR-SN – what kind of PSRAM are you using?

Thanks, Jörg