How to flash nRF52 through an external host MCU?

[Youssef19]

In my design the nRF52 is connected to an STM32 host MCU. I connected the UART for data communication and the SWD and RESET pins for programming.

The nRF52 needs to be programmed through the host (even the first time) so the programming needs to go through the SWD interface. (Cannot use the UART as the bootloader is not programmed).

Is there example software to allow the programming of the nRF52 from an external host? 

Many thanks,

Youssef

[Andy]

Is there any reason why you don't want to flash the bootloader in the NRF52?

[Andy]

Ah, somehow I missed the “even the first time” part. I’d suggest you make the NRF52 the host, the STM32 has a built-in bootloader and you can flash it from the NRF52 the first time using UART or I2C. I did this to allow for STM32 firmware updates over BLE through the NRF52 and it works quite well.