FREE RTOS for processors with MMU

aeyes wrote on Friday, April 24, 2009:

Hi ,

    I am aware of the fact that MMU less processors are only supported in FREERTOS . I was thinking of having an implementation of FREE RTOS on some ARM processor with MMU . Would it be of any help if that’s implemented ?

   For example if I consider the ARM 926EJS Versatile baseboard and wish to port FREERTOS on it , do I have to consider the 926 MMU also ? How would I go about the porting ? 

davedoors wrote on Friday, April 24, 2009:

Implementing a version that actually makes use of the MMU would be interesting and useful. But you can run FreeRTOS on an processor that has an MMU without actually using the MMU.

aeyes wrote on Friday, April 24, 2009:

   Right , I could bypass the MMU definitely .

   If there could be a valuable use case for usage for MMU in FREERTOS and how it would help , we could try it . Do you have any requirement of this sort ?

   I wanted to learn about MMU implementation on processors , what better way than trying to do a small implementation .

davedoors wrote on Friday, April 24, 2009:

Its a good question and to be honest I’m not sure. When you create a task you would have to set up a memory region for use by the task, then when you switch a task in set the MMU to use the correct memory region for the task that is about to run. I’m sure it would be more complex than that though, especially when linking the code to use the memory.

aeyes wrote on Friday, April 24, 2009:

Ok , let me figure out if it is of a real value add .

    I’ll try and do a study as to what benefits FREERTOS could enjoy if it really made use of the MMU against the way it currently manages memory . If I have a compelling case in favour of MMU , I will get serious about this . 

   Thanks for all the support so far .

krabe3ag wrote on Tuesday, June 16, 2009:

Isn’t MMU needed to use USB(access drive and read file)?