SFFS779 December 2024 TMS320F28P550SJ
The CPU timer module can be used to detect incorrect clock frequencies and drift between clock sources. CPU Timer 2 has a programmable counter whose prescale value and clock source can be selected. The frequency relationship between selected clock and system clock can be determined using the system clock as a reference time base. For more information on the clock selection options implemented, refer to the device-specific data sheet. Higher diagnostic coverage can be obtained by setting tighter bounds when checking clock integrity using Timer 2. Common cause failures can be reduced by using different clock sources and different prescale values for the reference clock and measured clock. The timer diagnostic is not enabled by default and must be enabled through software. The cyclical check applied by the timer module provides an inherent level of self-checking (auto-coverage), which can be considered for application in latent fault diagnostics.