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Port to LPC2214

Posted by George M. Gallant, Jr. on February 19, 2006
I am attempting to port FreeRTOS to an Olimex LPC-H2214 board. Looking at the existing LPC
ports I detect a problem during startup. The mode
is changed from:

SVC -> UND -> ABT -> FIQ -> IRQ -> SCV-> SYS -> SCV

Accoding to the ARM docs, once the mode is changed to SYS or USER only and exception can change the mode. Thus, the last mode change should fail.


RE: Port to LPC2214

Posted by Nobody/Anonymous on February 19, 2006
According to my out of date copy of the ARM ARM "The modes other than *User* mode are known as privileged modes. They have full access to system resources and can change mode freely".

This would seem to suggest, contrary to your post, that a SYS->SCV mode change is possible. I think this must be the case as my understanding from other posts here is that the OS can only be started from SVC mode. If the switch back to SVC did not work the OS would not work.

Can you step through the code and confirm this is the case? Where did you read that a SYS->SCV cannot occur?

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