FreeRTOS Support Archive
The FreeRTOS support forum is used to obtain active support directly from Real
Time Engineers Ltd. In return for using our top quality software and services for
free, we request you play fair and do your bit to help others too! Sign up
to receive notifications of new support topics then help where you can.
This is a read only archive of threads posted to the FreeRTOS support forum.
The archive is updated every week, so will not always contain the very latest posts.
Use these archive pages to search previous posts. Use the Live FreeRTOS Forum
link to reply to a post, or start a new support thread.
[FreeRTOS Home] [Live FreeRTOS Forum] [FAQ] [Archive Top] [September 2005 Threads] AT91SAM7S64 IAR portPosted by Jokke on September 20, 2005 I discovered a problem with crashing system. The cause showed up to be that IAR expects stack to be initiated to 0, but freeRTOS initates to 01010101, 02020202 ...
Therefore I have made a change to port.c, in "pxPortInitialiseStack": --- *pxTopOfStack = ( portSTACK_TYPE ) 0xaaaaaaaa;/* R14 */ pxTopOfStack--; *pxTopOfStack = ( portSTACK_TYPE ) pxOriginalTOS; /* Stack used when task starts goes in R13. */ pxTopOfStack--; for (i = 0; i < 12; ++i) { *pxTopOfStack = ( portSTACK_TYPE ) 0x0;/* R12...R1 */ pxTopOfStack--; }
---
After that it works.
Regards
Jokke
RE: AT91SAM7S64 IAR portPosted by Richard on September 20, 2005 This is definitely not the case. When a task starts it does not make any assumptions as to the stack or register states.
I suspect you are calling main() in the wrong processor mode. main() must be called in supervisor mode. Are you using the startup code that came with the demo project?
RE: AT91SAM7S64 IAR portPosted by Jokke on September 20, 2005 This has nothing to do with main. In a normal task I discovered (looking at the assembler listing) that the compiler places a read in a vector, using an index that is in some cases still not initialized. This works fine as long as the index is 0 until it is used, but I got problems with reads out of defined memory, since, in this case, R5 was 0x05050505, as is initialised in port.c. Maybe this is a compiler error, but my guess was that they made this assumption. The code is a state machine, and it might not be obvious enough for the compiler that it starts in a state where the index is set, before moving to the state where it is used. On the other hand I do not get any warning of "used before set"(maybe IAR does not give such warnings?). I am using the startup from the demo project, and I made a lot of versions of the software before this came up. I guess I will have to send you the code and the assembler listing before we reach consensus on this... Regards Jokke
RE: AT91SAM7S64 IAR portPosted by Richard on September 20, 2005 If you could send me the smallest project possible that exhibits this behaviour I would be very grateful! Send it to the email address from the FreeRTOS WEB site Contacts page (r dot barry at fr.....org). Thanks.
RE: AT91SAM7S64 IAR portPosted by Richard on September 20, 2005 From the received code it looks as if there could be a compiler error - I will post the results but might take a while.
RE: AT91SAM7S64 IAR portPosted by Jokke on September 26, 2005 I upgraded the IAR tools to lates version (4.30), and there the compiler bug seems to be solved! No problem with freeRTOS! SOLVED
Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.
|