In embedded systems, programmable peripherals are often coupled with the main programmable processor to achieve the desired functionality. Interfacing such peripherals with the processor qualifies as an important task of hardware software codesign. In this paper, three important aspects of such interfacing, namely, the allocation of addresses to the devices, allocation of device drivers, and approaches to handle events and transitions have been discussed. The proposed approaches have been incorporated in a codesign system MICKEY. The paper includes a number of examples, taken from results synthesized by MICKEY, to illustrate the ideas.