Questions in 2. stage bootloader code

[AlexESP32]

I am sorry about that but I really don't understand this.

- Could you please provide the chapter where I can find the information about the 11.5MB? (I think MMU, Cache, ...)
- What is the TPM?

ESP32 with 16MB Flash --> my thoughts are: Access all 16MB of the Flash, is this possible or are there limitations because of the 11.5MB?

Thank you.

[WiFive]

Technical Reference Manual
1.3.3 External Memory
26.3.2.2 External Memory
https://docs.espressif.com/projects/esp ... index.html

Access all 16MB of the Flash, is this possible or are there limitations because of the 11.5MB

You cannot access it all at once by memory mapping but you can access it by flash read APIs like esp_partition. I don't know if esp-idf is even supporting up to 11.5mb limit.

[AlexESP32]

Hm Thank you but I still understand this...

Why I cannot acces them all? Because there is MMU needed? --> Then I have to check MMU / Cache first...

Thank you.

[WiFive]

Flash, it is external and it is only connected by SPI. Two ways to access it, both over SPI. Either the cache/mmu will do the SPI transaction in the background or you will do it using API calls like esp_partiton. Flash cache and mmu have limitations due to design/silicon implementation. You just have to live with it or use another chip.

[AlexESP32]

Ah okay.

The differerence between the cache and the api helps me a lot
I will check the difference in detail

Greetings