I have a large project and have hit the RAM1 limit of the Teensy 4.0 that I run the code on.

I'd like to use the PROGMEM or DMAMEM keywords to move some low-priority data into Flash or DMA (RAM2) memory, however, the code is in a shared project (for unit testing purposes).

Can anyone tell me if it's possible to do this?

Here's my project architecture

Main (.ino)       Tests
              \       /
              Shared

I need to access the const data from both top-level projects (Main and Test) but I want the data to be in RAM2 ideally when running on the teensy.

I just get an intellisense error: "Identifier DMAMEM not recognised", which makes perfect sense as the Shared code has no knowledge of Teensy.

Any help or other suggestions are greatly appreciated.

After messing around trying to get this working, I gave up and instead overcame my mem issues by changing some data types and reducing the amount of const data. This bought me some time.

However, as the project continued to grow, I've come back to the issue.

The good news is it is now resolved.

My problems were due to having certain std methods that were reading from a different c++ library than the Ardiuno project used.

So, I removed the references to std and added this include to the header files where I wanted to use PROGMEM.

#if defined(ARDUINO) && ARDUINO >= 100
#include "arduino.h"
#endif
 

Then I added the following above each data declaration:

#if defined(ARDUINO) && ARDUINO >= 100
PROGMEM
#endif
const DataType myData[n] { ... }
 

There seems to be no issue using const and PROGMEM as I feared.

Both my main Arduino project and my GTest projects compile successfully using the same shared project.