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] [April 2008 Threads] Cortex-M3 Stack problem using a bootloaderPosted by ravaz on April 1, 2008 I found a problem on the Cortex-M3 port. In the port.c file the MSP (main stack pointer) is initialized assuiming that the vector table is strored at the adress 0x00000000, using a bootloader this is not hte case. For that reason I modified the code as follow:
Line 160: prvSetMSP( *((unsigned portLONG *) portNVIC_VTABLE ) );
The portNVIC_VTABLE must be defined using:
#define portNVIC_VTABLE 0xE000ED08
Hope can help....
RE: Cortex-M3 Stack problem using a bootloaderPosted by Dave on April 3, 2008 Very good point. Can we add this to the standard download?
RE: Cortex-M3 Stack problem using a bootloadePosted by ravaz on April 3, 2008 Another correction should be done is the systick timer reload value. To be correct the value should be loaded using:
*(portNVIC_SYSTICK_LOAD) = (configCPU_CLOCK_HZ / configTICK_RATE_HZ)-1;
regards
Ravaz
RE: Cortex-M3 Stack problem using a bootloadePosted by Richard on April 3, 2008 I like to make sure I make that mistake over and over again :o) It will be right (for this port at least) in the next version.
Regards.
RE: Cortex-M3 Stack problem using a bootloadePosted by ravaz on April 3, 2008 I would take the chance to thank you for the great job and for the perseverance you have to continously improve it....
RE: Cortex-M3 Stack problem using a bootloadePosted by ravaz on April 8, 2008 I did the modification for the version 4.8.0 as follow
void vPortStartFirstTask(void) { asm volatile( " ldr r0, =0xE000ED08 \n" /* Load the NVIC_TABLE offset address. */ " ldr r0, [r0] \n" /* Get the vector table offset. */ " ldr r0, [r0] \n" /* Get the stack pointer. */ " msr msp, r0 \n" /* Set the msp back to the start of the stack. */ " svc 0 \n" /* System call to start first task. */ ); }
Regards
Ravaz
Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.
|