Table 52. Spi_Sm_3; Table 53. Spi_Sm_4 - ST STM32F2 Series User Manual

SM CODE
Detailed implementation
Error reporting
Fault detection time
Addressed fault model
Dependency on MCU configuration None
Initialization
Periodicity
Test for the diagnostic
Multiple faults protection
Recommendations and known
limitations
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
UM1845 - Rev 4
SPI_SM_2
This method is implemented adding to data packets transferred by SPI a redundancy check (like a CRC
check, or similar one) with encoding capability. The checksum encoding capability must be robust
enough to guarantee at least 90% probability of detection for a single bit flip in the data packet.
Consistency of data packet must be checked by the application software before consuming data
Depends on implementation
Depends on implementation
Permanent and Transient
Depends on implementation
On demand
Not needed
CPU_SM_0: periodical core self-test software
It is assumed that the remote SPI counterpart has an equivalent capability of performing the check
described.
Transmission full redundancy (message repetition) should not be used because its detection capability is
limited to a subset of communication unit failure modes.
To give an example on checksum encoding capability, using just a bit-by-bit addition is unappropriated.
This method is superseded by SSP_SM_3 if hardware handled CRC insertion is possible
Table 52.
SPI_SM_3
CRC packet-level
ST
SPI communication module allows to activate automatic insertion (and check) of CRC-8 or CRC-18
checksums to packet data
Error flag raise and optional Interrupt Event generation
Depends on peripheral configuration (e.g. baud rate), refer to functional documentation
Permanent and Transient
None
Depends on implementation
Continuous
Not needed
SPI_SM_2: Information redundancy techniques on messages
Table 53.
SPI_SM_4
Information redundancy techniques on messages, including end-to-end safing
End user
This method aims to protect the communication between SPI peripheral and his external
counterpart.
Refer to CAN_SM_2 description for detailed information.
Description of hardware and software diagnostics
SPI_SM_3
SPI_SM_4
UM1845
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