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Maximum addressable memory expansion available

Posted: Tue May 22, 2018 9:26 am
by Dav_FR
Dear all,

I'm searching for the biggest addressable memory architecture possible.

I have been reading some documentation and threads regarding the inclusion of extra flash memories and the PSRAM, my idea is understand and confirm which is the maximum addressed memory available to be included on the ESP32 using external memories.

From what I understood, the maximum addressable memory which can be added to the ESP32 is:
- an external 16MiB flash memory mapped to be used as code/data/fs
- an external 4MiB PSRAM mapped as RAM

These memories are in the same SPI with a couple of pins differing.

More additional 16MiB flash external memories can be added but using the SPI2 and SPI3 (HSPI and VSPI) and they can not be mapped as code/data/fs/ram. They should be used through SPI DMA.

Is this correct?

There is another option to achieve more code/data/fs/ram memory?

The support to address more than one flash memory mapped as (code/data/fs), is present on the ESP-IDF roadmap?

Best regards and sorry about the inconvenience

Re: Maximum addressable memory expansion available

Posted: Wed May 23, 2018 8:32 am
by ESP_Sprite
You are more-or-less right. If I recall correctly, we can actually have some more psram (up to 8MiB or so) but it cannot all be mapped into memory at the same time, and as it'd become quite difficult to use, we have no plans to add functionality for this to esp-idf.

Re: Maximum addressable memory expansion available

Posted: Wed May 23, 2018 8:45 am
by Dav_FR
Thanks you so much @ESP_Sprite

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