freeRTOS support of MSP430X

Posted by williamjsell on April 24, 2011
I tried to port freeRTOS over to the msp430f5529 platform from the existing msp430f449 freeRTOS demo; I am using Crossworks V2.0 as the dev environment; it was pretty straightforward, or so it seemed; but when I called the asm line “call#_prvSetupTimerInterrupt”, the call never returns; at first I thought this was the stack getting manipulated to vector to the first task, but the call to portRESTORE_CONTEXT is never reached, which means the stack should have the return address to the calling function. But this is not working and I cannot see the reason; Paul Curtis at Crossworks thinks this is something to do with the compilation being for the MSP430X series of processors which have a different idea of function pointers. To save myself some time figuring this issue, I thought I would check and see if anyone else has encountered a similiar problem; the new series of MSP’s from TI are getting very popular with the extended memory range and internal USB hardware, so it seems like a good thing to fix



RE: freeRTOS support of MSP430X

Posted by Richard on April 24, 2011
If you have the compiler set to use the extended memory, then you should be calling “calla”, not “call”. Check out the MSP430X instruction set.

I would suggest using the provided IAR and CCS4 MSP430X ports (in the FreeRTOS download) as a reference. The Rowley compiler differs somewhat with regard to how function pointers are are used though, so when setting up the initial stack for the task you will have to de-reference to 16 bit pxCode parameter in the pxPortInitialiseStack() function to find the true 20 bit value. (the function pointer actually points to a look up table that contains the real addresses).


RE: freeRTOS support of MSP430X

Posted by Bart Tormans on October 9, 2011

Have there been any new developments in this area? I would also, very much like to use FreeRTOS/MSP430X/CrossStudio combination.

Could anyone please share some experience?

Many thanks in advace