Questions about External PSRAM with ESP32-P4NRW32X

[mahmoudezz]

Hello everyone,

I have recently started working with the ESP32-P4NRW32X and have several questions regarding its external memory capabilities. I've reviewed the official documentation, but need clarification on a few practical points.

1. Feasibility and Maximum Size of External PSRAM
The documentation states that the ESP32-P4 can use "up to 64 MB of virtual addresses for external PSRAM". Is it correct to interpret this as supporting an external PSRAM chip up to 64 MB, meaning the 32 MB in-package PSRAM is not the only option? What is the officially supported maximum size?

2. Interaction Between In-Package and External PSRAM
If I connect an external PSRAM chip to the ESP32-P4NRW32X (which has 32 MB of in-package PSRAM), will the in-package PSRAM become unavailable, or can both memory regions coexist and be used simultaneously? I understand that on some other ESP32 variants, the in-package PSRAM and an external chip cannot be used at the same time. Is this the case for the P4?

3. Examples and Documentation
Are there any official code examples or application notes that specifically demonstrate the use of an external PSRAM chip with the ESP32-P4? The "Support for External RAM" page mentions that ESP-IDF currently only supports Espressif-branded PSRAM chips (e.g., ESP-PSRAM32, ESP-PSRAM64). Where can I find the most comprehensive documentation on this topic?

4. Simultaneous Use of External NOR Flash and External PSRAM
Is it possible to have both an external NOR flash chip and an external PSRAM chip connected and operational at the same time? The documentation notes that ESP32-P4 supports PSRAM connected in parallel with the SPI flash chip. What would be the maximum supported sizes for each in a dual-chip configuration, and are there any special pin-sharing or configuration constraints?

Thank you for your time