To successfully operate real-time software on any microprocessor system, control and management of all interrupt services is required. Unfortunately, depending on your BIOS, it may not be possible to turn off certain interrupts known as System Management Interrupts (SMIs). These interrupts are not accessible from operating system, kernel, or application software and the CPU cannot be instructed to ignore them. However, for some chipsets, such as the Intel ICH5 family, it is possible to programmatically prevent or disable the generation of SMIs.
Unexpected SMIs will cause random and spurious CPU overloads. The enclosed S-function and Simulink block will disable SMIs on the Intel ICH5 chipset family and help avoid these overloads.