topic Re: Debugging a program with debugger in LPC Microcontrollers

Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:13 GMT

Content originally posted in LPCWare by justmakeit on Thu May 07 01:38:18 MST 2015
Hello,

Currently i'm trying to make a program with a bootloader. But i keep failing with debugging the user application in LPCxpresso. There are a lot of questions and answers on the internet about creating a bootloader, but i cant found how to implement the flash settings in lpcxpresso. i'm using the "lpc link2" as programmer

what i'm doing:
1. program the bootloader the default way.
Debug As-> C/C++ (NXP semiconductors) MCU application

2. the bootloader start the application with the next code:
PROGRAM_ADDRESS_START = 0x3000

void execute_user_code(void)
{
void (*user_code_entry)(void);

unsigned *p;// used for loading address of reset handler from user flash

/* Change the Vector Table to the USER_FLASH_START
in case the user application uses interrupts */

SCB->VTOR = (PROGRAM_ADDRESS_START & 0x1FFFFF80);

// Load contents of second word of user flash - the reset handler address
// in the applications vector table
p = (unsigned *)(PROGRAM_ADDRESS_START +4);

// Set user_code_entry to be the address contained in that second word
// of user flash
user_code_entry = (void *) *p;

// Jump to user application
    user_code_entry();

}

3. replace the user application in flash
properties->c/c++ build->mcu settings->LPC1766->MFlash256 location: 0x3000 size: 0x3d000

4. Debug the user code
Debug As-> C/C++ (NXP semiconductors) MCU application

5. Debugger jumps to the wrong code

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:13 GMT

Content originally posted in LPCWare by R2D2 on Thu May 07 04:44:58 MST 2015

Quote: justmakeit
Currently i'm trying to make a program with a bootloader...

Usually it's enough to flash/debug the bootlader and then debug the application (with application Flash settting) :)

Debugger should of course start the debug session at your MCU settings->Flash location...

If that's not working and the debugger is still starting at 0x0000 use a simple bootloader to jump to your application start address...

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:14 GMT

Content originally posted in LPCWare by justmakeit on Tue May 19 06:38:49 MST 2015
Thanks for your reaction,

I made the simple bootloader to jump to my user code and he is jumping to the right code. When i set a breakpoint at te start of my main function it breaks at the right location. But when i step through my code it goes wrong after a few steps. the place of failure is random depending on the speed of stepping through my code. When it's failing it jumps to pc = 0x114 .
How can i figureout the reason it is failing?

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:15 GMT

Content originally posted in LPCWare by R2D2 on Tue May 19 06:50:59 MST 2015
Are you still using the code above?

Could be useful to load the stack pointer before the jump is executed :O

And of course disable interrupts :)

Quote: justmakeit
When it's failing it jumps to pc = 0x114.
How can i figureout the reason it is failing?

What's in 0x114 :quest:

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:15 GMT

Content originally posted in LPCWare by justmakeit on Tue May 19 07:35:55 MST 2015
Yes my simple bootloader is the code above.
i haven't turn on any interrupts. are there interrupts default on?
i'm a bit confused now... The stack of the bootloader is the same memory as my user code uses right? So why do i need to load a stack pointer?

my user code start at address 0x3000 so 0x114 is not in the user code.
0x114 is the SysTick_Handler of the bootloader code.

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:16 GMT

Content originally posted in LPCWare by R2D2 on Tue May 19 07:41:00 MST 2015

Quote: justmakeit
my user code start at address 0x3000 so 0x114 is not in the user code.

Quote: justmakeit
0x114 is the SysTick_Handler of the bootloader code.

And who is using SysTick?

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:16 GMT

Content originally posted in LPCWare by justmakeit on Tue May 19 08:11:28 MST 2015
only my user code uses the SysTick_Handler. I disable it in the bootloader code. but it is still jumping to the wrong Systick_handler. I probably asking very stupid questions :) , please give me some more information.

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:17 GMT

Content originally posted in LPCWare by R2D2 on Tue May 19 08:16:30 MST 2015

Quote: justmakeit
only my user code uses the SysTick_Handler. I disable it in the bootloader code. but it is still jumping to the wrong Systick_handler. I probably asking very stupid questions :) , please give me some more information.

I've no idea what your bootloader or application is doing in detail :)

So it could be a good idea to disable SysTick in your application, then the problem should disappear...

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:17 GMT

Content originally posted in LPCWare by justmakeit on Wed May 20 05:27:34 MST 2015
I disabled the systick in my user application and it don't fail anymore

. But my user program uses the systick interrupt to run my timers. so how can i remap the interrupt to address 0x3114 ?
i remap the vector table with this code:

SCB->VTOR = (PROGRAM_ADDRESS_START & 0x1FFFFF80);

Thank you in advance for your help

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:18 GMT

Content originally posted in LPCWare by R2D2 on Wed May 20 05:45:53 MST 2015

Quote: justmakeit
I disabled the systick in my user application and it don't fail anymore :D . But my user program uses the systick interrupt...

Don't panic early :)

Disabling SysTick is of course a test to show you the problem...

Next step: look in your application vector table (at 0x3000) .
There's the address (+1) for SysTick interrupt handler at word 0x3C :O

That should be in your case something > 0x3000. If it's 0x115 your vector table is wrong :D

Re: Debugging a program with debugger

lpcware — Wed, 15 Jun 2016 17:44:19 GMT

Content originally posted in LPCWare by justmakeit on Wed May 20 05:48:24 MST 2015
I have found my problem. CMSIS overwrite my configuration. so i was searching in the wrong code ;-) its working now :D Thanks for your help!