SPRUJ17I March 2022 – August 2025 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1
This is the default mode on start-up. In lockstep mode, the bus output signals of both CPUs and VIMs are compared. A difference in the CPU compare bus outputs is indicated by signaling an error to the ESM, which sets the error flag "CCM-R5F - CPU compare" and "CCM-R5F - VIM compare", respectively.
The CPU compare error asserts “CCM-R5F self-test error” flag as well. By doing this, the CPU compare error has two paths (“CCM-R5F - CPU compare” and “CCM-R5F self-test error” flag) to the ESM, so that even if one of the paths fails, the error is still propagated to the ESM. This is also true for "CCM-R5F - VIM compare" error flag.
Not all internal registers of the Cortex-R5F CPU have fixed values upon reset. To avoid an erroneous CCM-R5F compare error, the application software needs to ensure that the CPU registers of both CPUs are initialized with the same values before the registers are used, including function calls where the register values are pushed onto the stack.