A design environment for FPGA applications enables configuration of an FPGA platform to include a user design and one or more interface units, which the user design can use to access one or more external modules/devices without needing any particular knowledge of the structure and operation of such modules/devices. The interface unit corresponding to an external device/module, under the control of an operating environment, can establish a communication between the user design and the external module/device. An external processing module can use an interface unit to monitor and/or control a user design.