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Keil RTX and bootloading

Johan Moraal
Note: This was originally posted on 25th January 2011 at http://forums.arm.com

Hi all.

I've recently written a secondary bootloader for NXP LPC17xx devices. The design is relatively simple: All our products have embedded serial flash connected with an SPI bus to the micro. The user application is responsible to load a binary image onto the serial flash. When the bootloader starts, it checks the serial flash for a binary image. If one is not found, it jumps to the user application. If one is found, it verifies the integrity of the image by doing a CRC check. If the check passes it begins to update the LPC's flash from the binary image on the serial flash.

I've confirmed that the bootloader application is working properly. Firstly I checked the LPC's flash with a ULINK Pro and made sure the bootloader is not accidentally overridden. Then I uploaded a small application that reads and verifies a large chunk of flash and blinks a led. All these tests succeeded and I'm confident my bootloader works properly.

The problem arises when I try to upload an application which uses the Keil RL-ARM real time OS. When I upload this type of application, nothing happens. I traced the problem with a ULINK and I found that the trace stops at SVC_Handler in startup_LPC17xx.s.

All our RL-ARM based applications run in privileged mode. I know the RTOS uses SVC to access hardware etc in privileged mode.

Is there something I should do in the bootloader in order to support RL apps?
Parents
  • Note: This was originally posted on 25th January 2011 at http://forums.arm.com

    I've found my problem:
    in the file system_LPC17xx.c I found this:

    //  Set Vector table offset value
    #if (__RAM_MODE__==1)
      SCB->VTOR  = 0x10000000 & 0x3FFFFF80;
    #else
      SCB->VTOR  = 0x00000000 & 0x3FFFFF80;
    #endif

    this obviously sets the VTOR to the incorrect location. It's merely a coincidence that the application running priveledged mode had the above code and the one running unpriveledged mode did not have it.. SVC is the first IRQ in my RTX app
Reply
  • Note: This was originally posted on 25th January 2011 at http://forums.arm.com

    I've found my problem:
    in the file system_LPC17xx.c I found this:

    //  Set Vector table offset value
    #if (__RAM_MODE__==1)
      SCB->VTOR  = 0x10000000 & 0x3FFFFF80;
    #else
      SCB->VTOR  = 0x00000000 & 0x3FFFFF80;
    #endif

    this obviously sets the VTOR to the incorrect location. It's merely a coincidence that the application running priveledged mode had the above code and the one running unpriveledged mode did not have it.. SVC is the first IRQ in my RTX app
Children
  • in reply to Johan Moraal

    Thank you so much for posting this. I really can't understand why it is set to 0 in this file. Took me 2 days to find why the boot code ran, the main app ran but I couldn't start the RTOS. Of course it's because the vectors were in the wrong place - even though I had set them to the right place in the boot code!