Dependence of electromagnetic immunity of microcontrollers on system clock frequency

Abstract

To test and to model the conducted radio frequency electromagnetic immunity of a reconfigurable integrated circuit like microcontrollers is complex because the configuration parameter is variable. A study is presented of the dependence of immunity on one of the configuration parameters -the system clock. The theoretical analysis shows that the immunity is independent of the clock frequency in the frequency range of interest. Measurement results support the theoretical prediction.

Characterisation of system clock frequency effects on electromagnetic immunity of microcontroller input buffer

“…However, as a basic configuration parameter in a microcontroller, the clock signal, which is variable in frequency, may cause great problems in the immunity test and modelling. A previous study [6] demonstrated that the immunity performance of microcontrollers is independent of the clock frequency when an RF noise is injected into the supply pins. However, in the case that RF noise is injected into a common I/O pin, the clock signal plays an important role when reading the input logic state from the data register, and this system clock effect is always ignored.…”