Configure LPC55 to enter/re-invoke ROM Bootloader from application code

[jonathanmccarro]

Hi,

Is it possible to give an example how to invoke the ROM Bootloader from code.

I dont have the option to use ISP0 pin on hardware to enter Bootloader after resetting device.

Do the CMPA.DCFG_CC_SOCU_PIN and CMPA.DCFG_CC_SOCU_DFLT registers need programmed to do this and if so give example of value to send. Can you tell me how to do it with blhost cmds.

Thanks

[Alexis_A]

Dear jonathanmccarron‌,

In the SDK from the LPC55s6x there's an example of how to use the IAP function, if you check the fsl_iap.c you will see the next define:

#define BOOTLOADER_API_TREE_POINTER ((bootloader_tree_t *)ROM_API_TREE)‍

This define will provide you a user application access to APIs exported by the bootloader.

If you check the bootloader_tree_t type, you will see a function called runBootloader.

I hope this helps you.

Best Regards,

Alexis Andalon

[jonathanmccarro]

Dear Alexis,

Thank you for the reply. 

Do you have a small example how I can use this? I just want to call say from within user application.

Does the device reset itself when called with this API or do I have to do software reset etc?

Thanks. 

[Alexis_A · Accepted solution]

Hi jonathanmccarron‌,

I ask the application team about this and they mention there's an easier way to set this.

If you write the following register, it will be set to boot from the ROM:

PMC->AOREG1 |= (0x0A << 16); //Set to boot from ROM
NVIC_SystemReset();          //Reset‍‍

Let me know if this helps you.

Best Regards,

Alexis Andalon

[tejacob]

hi,

trying this on lpc55s69-evk and the device restarts, but it doesn't stay in rom boot - it continues to boot the application.

what may be the cause for this?

thanks, jacob

[tejacob]

i've also tried the `runBootloader` way, as well as this hack: https://github.com/lpc55/lpc55-hal/pull/51/files

all of them behave the same.