How to upgrade another MCU firmware by nordic n51822 DFU.

[leif]

Hi, My project include two MCU with n51822 and STM32. I expect upgrading STM32 application firmware by n51822 DFU function. Do you give your advice to implement it by modifying nRF51_SDK_8.1.0_b6ed55f\examples\dfu\bootloader example? Thank you.

[Hung Bui]

Hi Leif,

It should be ok with what you planning to have.

You have two options. First is to have a RAM buffer on the nRF51 and then send the packets you receive from the phone to the STM32 via UART on the fly. This approach require you to have a DFU bootloader or something like that to handle the packets from the nRF51 on the STM chip running at the same time. This solution doesn't have restriction on the size of the new image of the SRM32 chip.

Second approach is what you described, you store the image for STM32 on the nRF51 and then later on you have the bootloader on the STM32 to talk to the nRF51 and get the image from the nRF51. With this approach you will have limitation of the size of the swap area on the nRF51 (about 70kB). But it's safer because the image is stored on flash before it's sent to STM32.

Unfortunately, we don't have any example for doing that. What we have is the bootloader for the nRF51 only. But I don't see any technical problem to implement it.

[leif]

if using single-bank update for only applictaion. it will extend the limitaiton of the image size with over 70kB. i presume that nRF51822 occupy max image size with 48kB then upgrading STM32 max imgage size is 96kB. is my descritpion ok? Another, does single-bank updates not support softdevice update or bootloader update? must use dual-bank updates if expecting softdevice or bootloader update?