External memory interface

Projects Programming
1

Hi guys,

I have been looking into the datasheet "External memory interface".

If i wanted to implement some kind of SRAM expansion using the external memory interface in arduino, would i be able to do that?

I´m not sure but i think not, right? Because the arduino development environment doesn´t support it ?

Thanks

Luís

2

The Mega supports that.
Check here for an example
http://www.ruggedcircuits.com/html/quadram.html

3

Yes it depends on the specific AVR chip on if an external memory bus is supported. The AVR mega1280/2560 do, the AVR mega328p does not. That link that CrossRoads posted will lead to both the software and hardware details needed to attach and utilize external ram.

Lefty

4

Hi,

Yes, i know that physically the Atmega2560 supports this.

My problem is, when my internal SRAM ends, meaning when i allocate enough variables to fill the entire internal RAM.
How does the compiler knows that the next global variable "int A" (for example) should go to external SRAM.

It is impossible to do this, correct?
The compiler would have to know prior that i have more SRAM?

5

I believe from a software support point of view the external ram is most easily added to the 'heap' capacity rather then the stack or variable and constant space? Again if you look at the software examples that Rugged Circuit publishes to support their product you can see one way that the extra ram can be utilized in a sketch.

Lefty