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How does LM3S8962 MPU work with FreeRTOS 7.01

Posted by Victor Zhang on August 18, 2011
Environment: EK-LM3s8962 Eval Kit.
Code sourcery G++ Lite
RTOS Version : 7.0.1

The demo works perfect on the board.
But when I'm changing the ARM_CM3/port.c to ARM_CM3_MPU/port.c , there happens to be a lot of errors like:
“../../../Source/portable/GCC/ARM_CM3_MPU/port.c:206:17: error: conflicting types for 'pxPortInitialiseStack'
...
...


So which other files do I have to modify if I want to use the MPU of LM3s8962?

Memory Protection Unit (MPU)
The Memory Protection Unit (MPU) is included on the LM3S8962 controller and supports the standard
ARMv7 Protected Memory System Architecture (PMSA) model. The MPU provides full support for
protection regions, overlapping protection regions, access permissions, and exporting memory
attributes to the system.


Do I look into ARM7TDMI code?

Many Thanks.

RE: How does LM3S8962 MPU work with FreeRTOS 7.01

Posted by Richard on August 18, 2011
Think of FreeRTOS and FreeRTOS-MPU as being two different ports to the Cortex-M3. The MPU version requires different configuration, and uses a different API (especially for functions that create tasks, as MPU regions have to be set up for the task). I would recommend starting with one of the existing MPU demo applications, looking at which files are included and how it is configured, hopefully compile and run it (if possible), and then adapting that to your target platform - rather than starting with a non-MPU version and trying to update it to be an MPU version. The demo located in the FreeRTOS/Demo/CORTEX_MPU_LM3Sxxxx_Rowley directory would seem to be a good starting point (built with Rowley CrossWorks). I just tried building it, although not running it, and it built fine. main() generated some warnings where variables are set but not used, but these are in the fault handler and are set for inspection in the debugger.

More information, if you have not already seen it, can be found here:
http://www.freertos.org/FreeRTOS-MPU-memory-protection-unit.html

Regards.


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