Disable And Periodic Cross-Check Of Unintentional Activation Of Unused Peripherals; Table 114. Ffi_Sm_0; Table 115. Ffi_Sm_1 - ST STM32F2 Series User Manual

3.6.31

Disable and periodic cross-check of unintentional activation of unused peripherals

This section reports the safety mechanism that addresses peripherals not used by the safety application, or not
used at all.
SM CODE
Description
Ownership
Detailed implementation
Error reporting
Fault detection time
Addressed fault model
Dependency on MCU configuration
Initialization
Periodicity
Test for the diagnostic
Multiple faults protection
Recommendations and known limitations None
SM CODE
Description
Ownership
Detailed implementation
Error reporting
Fault detection time
Addressed fault model
Dependency on MCU configuration
Initialization
Periodicity
Test for the diagnostic
Multiple faults protection
UM1845 - Rev 4
Table 114. FFI_SM_0
FFI_SM_0
Unused peripherals disable
End user
This method contributes to the reduction of the probability of cross-interferences caused by
peripherals not used by the software application, in case a hardware failure causes an unintentional
activation.
After the system boot, the application software must disable all unused peripherals with this
procedure:
• Enable reset flag on AHB and APB peripheral reset register
• Disable clock distribution on AHB and APB peripheral clock enable register
NA
NA
NA
None
NA
Startup
Not needed
FFI_SM_1: Periodical read-back of interference avoidance registers
Table 115. FFI_SM_1
FFI_SM_1
Periodical read-back of interference avoidance registers
End user
This method contributes to the reduction of the probability of cross-interferences between
peripherals that can potentially conflict on the same input/output pins, including for instance unused
peripherals. This diagnostic measure must be applied to following registers:
• Clock enable and disable registers
• Alternate functions programming registers
Detailed information on the implementation of this method can be found in
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Description of hardware and software diagnostics
Section 3.6.5
UM1845
page 76/108