ESP32-S3 TRM: "1 GB external RAM"

[kangadac]

On the latest version of the ESP32-S3 TRM (https://www.espressif.com/sites/default ... ual_en.pdf), page 389 mentions:

External Memory

• Supports up to 1 GB external flash
• Supports up to 1 GB external RAM

However, the memory map on the following page only shows 64 MB of virtual address space (data from 0x3c00_0000-0x3dff_ffff, instruction from 0x4200_0000-0x43ff_ffff) mapped. Is this a bug in the documentation, or is there something I'm missing about how to map a full GB of memory into the address space?

I see mentions of this 1 GB support in other forum threads (e.g. https://esp32.com/viewtopic.php?t=33675&start=10), but all of the hardware actually uses 32 MB (or less).

Thanks!

[ESP_Sprite]

The ESP32-S3 can physically address 1GiB of RAM or flash, but you're right in that you can only map in 64MiB of it at the same time. Accessing the rest would require unmapping some of it and mapping in something else (see e.g. spi_flash_mmap() for how to do that with flash)