SPI configuration, How to define the interrupt handler

[ToTo]

My project is to communicate with the AD7780 via SPI. Nrf is the master and AD7780 is slave. I am know implementing my solution referring to an example i found about SPI under SDK11. I don't want to use the driver API ( "nrf_drv_spi.h" "nrf_drv_spi.c" ) implemented by Nordic because there are many thing i don't need. I am using only the file "nrf_spim.h" which is ok for initializing the SPI... Now i want to activate the interrupts, to get an interrupt each RX done. i found the function "nrf_drv_common_irq_enable" under "nrf_drv_common.h" which it sound ok (i haven't tried it yet).
But My problem is how can I define my Handler, i mean how can I hey when I get an Interrupt from SPI peripheral execute this handler ?? Any Idea Please ?

[Roger Clark]

Look in the spi example in examples/peripheral/spi it uses the callback

[ToTo]

I did,, there is a driver developed by Nordic i don't want to use it..but i tried to understand how they do i didn't get it