SPRUJ17H March 2022 – October 2024 AM2631 , AM2631-Q1 , AM2632 , AM2632-Q1 , AM2634 , AM2634-Q1
During the Compare Mismatch Test, the number of test patterns is equal to twice the number of CPU output signals to compare in lockstep mode. An all 1s vector is applied to the CCM-R5F’s CPU1 / VIM1 input port and the same pattern is also applied to the CCM-R5F’s CPU2 /VIM2 input port but with one bit flipped starting from signal position 0. The un-equal vector will cause the CCM-R5F to expect a compare mismatch at signal position 0, if the CCM-R5F logic is working correctly. If, however, the CCM-R5F logic reports a compare match, the self-test error flag is set, the self-test error signal is asserted, and the Compare Mismatch Test is terminated.
This Compare Mismatch Test algorithm repeats in a domino fashion with the next signal position flipped while forcing all other signals to logic level 1. This sequence is repeated until every single signal position is verified on both CPU signal ports.
The Compare Mismatch Test is terminated if the CCM-R5F reports a compare match versus the expected compare mismatch. This test ensures that the compare unit is able to detect a mismatch on every CPU signal being compared. Table 7-13 illustrates the sequence of Compare Mismatch Test. There is no error signal sent to ESM if the expected errors are seen with each pattern.
CPU 1 (Main CPU) Signal Position | CPU 2 (Checker CPU) Signal Position | Cycle | ||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
n | n–1:8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | n | n–1:8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |||
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 2 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 3 |
:: | ||||||||||||||||||||||
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | –1 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | n |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | n+1 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | n+2 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | n+3 |
1 | 1 | 1s | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | n+4 |
:: | ||||||||||||||||||||||
1 | 0 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2n-1 |
0 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1s | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 2n |