Bootloader to RAM.

[larshovesen]

I am using the FRDM-K28F for development to develop a device that is powered over a USB connection, and controlled entirely from a PC. We would like to have the device program uploaded from the PC everytime we start it up so we need a bootloader that can take a binary over the USB, put it into RAM and start it up. Do you have that functionality, or is it "flash programming bootloader" only for the Kinetis family? The best would of course be if the supplied ROM code could do this, but that seems to be "flash programming" only, as far as I can read the datasheets.

[NVazquez]

I am trying to boot RAM for LPC 540xx.

I used DFU-utility to write the program to SRAM.

Right now I need configure otp boot_src bits, so I can boot from on-chip sram and not from external flash.

Can someone tell me how can I configure BOOT_SRC (10:9)bits to 0?

Also is it not safe to boot from SRAM? In the data sheet it says use only for debugging purpose.

[larshovesen]

Hi Ma Hui

Thank you for your insights, I will also think we will do a classic design and load the program into flash. But perhaps you could point me to the most appropriate example to look at for a target bootloader. I have the FRDM-K28F development board, is there an example somewhere that should work directly on the K28FN2M0VMI15 which is the "main processor" on that board? Or is the best thing for me to do to take the "...MK22F12810\iar\flashloader_loader" example you have already pointed me to and convert that for the MK28F processor?

Yours sincerely

Lars

[Hui_Ma]

Hi Lars,

If you want to run the application at K28 internal Flash, there doesn't need the bootloader. K28 provides the ROM bootloader and could load the application image to Flash.

If you still want to run the application at K28 SRAM, then there need a secondary bootloader, besides of ROM bootloader. The secondary bootloader will load the application image to RAM and jump to run at RAM.

For the KBOOT software doesn't provide bootloader example for K28 product, customer need to port the bootloader of MK22 product or MK64 product to K28. Customer could refer [flashloader_loader] project as a start point.

Wish it helps.

Have a great day,
Ma Hui

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[Hui_Ma]

Hi,

The K28 chip provides ROM bootloader, which supports USB FS HID bootloader.

While, the application image will be loaded to Flash not RAM.

The KBOOT software provides [flashloader_loader] demo:

flashloader_loader – bootstrap loader designed to execute from flash memory on either the Freedom or Tower platform.
This loader copies an image of the flashloader into RAM, then executes the flashloader from RAM.

Customer can refer the [flashloader_loader] demo to copy an application image into RAM, then execute the application from RAM.

The KBOOT software could be downloaded from here.

The [flashloader_loader] could be found with below path:

..\NXP_Kinetis_Bootloader_2_0_0\targets\MK22F12810\iar\flashloader_loader

Thank you for the attention.

Have a great day,
Ma Hui

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