iMX6ULL DRAM-less operation

[blueskull]

Greetings community, 

Is there a way to use ONLY the internal 128KB OCRAM without DRAM at all with iMX6ULL?

I know there's a patch for SDK 1.1, but that's only for other iMX6 devices, and the makefile structure of SDK 1.1 is quite different from the current SDK 2.2.

Therefore, is there a way to use only OCRAM with iMX6ULL and SDK 2.2?

Also, what amount of available RAM can I expect from OCRAM-only operation (how much OCRAM must be allocated to non-user accessible functions, such as L1 map)?

Thanks in advance, 

Bo Gao

[art · Accepted solution]

Q. Is there a way to use ONLY the internal 128KB OCRAM without DRAM at all with iMX6ULL?

A. Of course, you can use a small OS-less applications running in OCRAM only not using DRAM. However, the functionality of such applications seems to be very limited due to small amount of memory available. On the other hand, it is possible to run the code directly from, for example, external parallel NOR flash using the External Memory Interface module and use OCRAM for stack/data only. The limitations here are: 1) relatively slow EIM operation and 2) relatively small address space of up to 128MBytes.

Q. Therefore, is there a way to use only OCRAM with iMX6ULL and SDK 2.2?

A. There is no ready-to-use path for SDK 2.2 to use such DRAM-less OCRAM-only environment. A custom memory map files should be created.

Q. Also, what amount of available RAM can I expect from OCRAM-only operation (how much OCRAM must be allocated to non-user accessible functions, such as L1 map)?

A. In such a small bare metal applications, everything including memory resources is under user control.

Have a great day,
Artur

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