ST STM32F2 Series - Table 43. UART_SM_3

SM CODE UART_SM_2
Ownership End user
Detailed implementation
This method is implemented adding to data packets transferred by UART 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
Error reporting Depends on implementation
Fault detection time Depends on implementation
Addressed fault model Permanent and Transient
Dependency on MCU configuration None
Initialization Depends on implementation
Periodicity On demand
Test for the diagnostic Not needed
Multiple faults protection CPU_SM_0: periodical core self-test software
Recommendations and known
limitations
It is assumed that the remote UART 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
Table 43. UART_SM_3
SM CODE UART_SM_3
Description Information redundancy techniques on messages, including end-to-end safing
Ownership End user
Detailed implementation
This method aims to protect the communication between a peripheral and his external counterpart.
Refer to CAN_SM_2 description for detailed information
Error reporting Refer to CAN_SM_2
Fault detection time Refer to CAN_SM_2
Addressed fault model Refer to CAN_SM_2
Dependency on MCU configuration Refer to CAN_SM_2
Initialization Refer to CAN_SM_2
Periodicity Refer to CAN_SM_2
Test for the diagnostic Refer to CAN_SM_2
Multiple faults protection Refer to CAN_SM_2
Recommendations and known limitations
Important note: it is assumed that the remote UART counterpart has an equivalent capability of
performing the checks described.
Refer to CAN_SM_2 for further notice
UM1845
Description of hardware and software diagnostics
UM1845 - Rev 4
page 35/108