Nordic dual bank DFU master example code

Hi, I have a project where an STM32 controller has the updated binary file for nRF1822 in flash and it will upgrade the firmware on nRF1822 with the serial implementation of Nordic provided dual bank DFU. May I know where I can get example code that has to be implemented on the STM32 to interact with nRF1822 in DFU mode and upgrade it