SPRUJ17H March 2022 – October 2024 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1
In error forcing mode, a test pattern is applied to the CPU / VIM related inputs of the CCM-R5F compare logic to force an error in the compare error output signal of the compare unit. Depending if error forcing mode is applied to the CPU Output Compare Diagnostic or VIM Output Compare Diagnostic, the ESM error flag “CCM-R5F - CPU compare” or “CCM-R5F - VIM compare” is expected after the error forcing mode completes. As a side effect, the “CCM-R5F self-test error” flag is also asserted whenever the CPU compare error is asserted.
Error forcing mode is similar to the Compare Mismatch Test operation of self-test mode in which an un-equal vector is applied to the CCM-R5F CPU signal ports. The error forcing mode forces the compare mismatch to actually assert the compare error output signal. This ensures that a fault in the path between CCM-R5F and ESM is detected.
Only one hardcoded test pattern is applied into CCM-R5F during error forcing mode. A repeated 0x5 pattern is applied to CPU1 / VIM1 signal port of CCM-R5F input while a repeated 0xA pattern is applied to the CPU2 / VIM2 signal port of CCM-R5F input. The error forcing mode takes one cycle to complete. Hence, the failing signature is presented for one clock cycle. After that, the mode is automatically switched to lockstep mode. The key register (MKEY1 for CPU output compare and MKEY2 for VIM output compare) will indicate the lockstep key mode once it is switched to lockstep mode. During the one cycle required by the error forcing test, the CPU / VIM output signals are not compared. The user should expect the ESM to trigger a response (report the CCM-R5F fail). If no error is detected by the ESM, then a hardware fault is present.