LPC11U68 secondary bootloader MTB conflicts with ram vectors?

[kiryat8]

I created a secondary bootloader for the LPC11U68 chip which jumps to our main program at 0x4004.

In the main program I copy the interrupt vectors to an array set to a ram array set to be located at vtable.

  int32_t vector_in_ram[AQUA_CPU_INTERRUPTS] __attribute__ ((section ("vtable")));

I then set the interrupts to be used from the ram.

  LPC_SYSCTL->SYSMEMREMAP = 0x1;

My problem is that the LPC11U68 chip maps the MTB trace in the local SRAM starting at address 0x1000 0000.

The vtable is located by the link script to 0x10000300 whereas for my use it should be at the MTB trace address.

"When the MAP bits in the SYSMEMREMAP register are set to 0x0 or 0x1, the boot
ROM or RAM respectively are mapped to the bottom 512 bytes of the memory map
(addresses 0x0000 0000 to 0x0000 0200)."

How can I disable the MTB trace in release code and change the link script just to remove it leaving everything else as is?

In my project Preprocessor defines there is __MTB_BUFFER_SIZE=256.

I removed it and recompiled but it did not help.

Thanks

[kiryat8]

Another related question, please.

I tied to bypass the problem moving the interrupt vectors to ram in my main program by using interrupt jumps in my bootloader program. This I understand will add just the jump commands latency. My main program uses the USB rom serial code. I seem to have a problem using the bootloader jump method with the USB when my main program is located at 0x4000. The program seems to start and I can seem debug printout on an uart port but stalls apparently in the USB initialization. The main program works when located at address 0. I saw on the forum where there were problems with the CAN rom interface in a similar situation. It my just be a bug somewhere.

/*****************************************************************************
 ** Function name:   USB_IRQHandler
 **
 ** Description:     Redirects CPU to application defined handler
 **
 ** Parameters:         None
 **
 ** Returned value:  None
 **
 *****************************************************************************/
void USB_IRQHandler(void)
{
    /* Re-direct interrupt, get handler address from application vector table */
    asm volatile("ldr r0, =0x4098");
    asm volatile("ldr r0, [r0]");
    asm volatile("mov pc, r0");
} // USB_IRQHandler

/*****************************************************************************
 ** Function name:   USB_FIQHandler
 **
 ** Description:     Redirects CPU to application defined handler
 **
 ** Parameters:         None
 **
 ** Returned value:  None
 **
 *****************************************************************************/
void USB_FIQHandler(void)
{
    /* Re-direct interrupt, get handler address from application vector table */
    asm volatile("ldr r0, =0x409C");
    asm volatile("ldr r0, [r0]");
    asm volatile("mov pc, r0");
} // USB_FIQHandler

/*****************************************************************************
 ** Function name:   USBWakeup_IRQHandler
 **
 ** Description:     Redirects CPU to application defined handler
 **
 ** Parameters:         None
 **
 ** Returned value:  None
 **
 *****************************************************************************/
void USBWakeup_IRQHandler(void)
{
    /* Re-direct interrupt, get handler address from application vector table */
    asm volatile("ldr r0, =0x40B8");
    asm volatile("ldr r0, [r0]");
    asm volatile("mov pc, r0");
} // USBWakeup_IRQHandler

Thanks

[jeremyzhou]

Hi David,

To disable the MTB feature, I have another idea, the LPC11U68 contains the Cortex M0+ core which integrates the Vector Table Offset Register (VTOR), it support to relocate the interrupt vector.

Hope it helps.

Have a great day,
TIC

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[kiryat8]

I could not find a Dbg_MTB in the NXP or my project directory nor could I find a dialog as in the photo.

I use the MCUXpresso IDE v10.1.1_606 IDE and just need to remove the MTB stuff if possible from my release (not debug) link script so that I can use the ram interrupt vector which I understand start a 0x0 in the ram.

Thanks

[jeremyzhou]

Hi  David Kaplan,

Thank you for your interest in NXP Semiconductor products and 

the opportunity to serve you.

You can remove the Dbg_MTB.ini to disable the MTB trace feature.

Fig 1

Hope it helps.

Have a great day,

TIC

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