Simulink-Rtwtgt Co-Design of Real Time Digital Interfaces

This paper describes the Simulink design of real time digital interfaces linked to I/O devices. This method is a hardware-software co-design of digital blocks, based on Simulink and real time windows target and is an alternative to S-function tool, which is a computer language description of a Simulink block. It gives a better level of abstraction of digital design and is straightforward applicable to I/O devices described by timing diagrams. This method seeks the use microcontroller resources such CPU, A/D, PWM in a control system designed in Simulink environment. A Simulink interface to a PIC 18Fxx8 microcontroller, operating at low level and involved in a two level hierarchical control system, is presented. The capability of the method as an alternative tool for S-function is detailed through an interfacing example of an A/D converter and a Simulink block. The procedure of real time simulation is described and the simulation result of the A/D conversion is presented and discussed.