eFuse Controller Testing
2189
SPNU563A – March 2018
Copyright © 2018, Texas Instruments Incorporated
eFuse Controller
38.3.2.3 Class 3 Error
A class 3 error indicates that there was a single bit failure reading the eFuses that was corrected by ECC
bits. Proper operation is still likely, but the system is now at a higher risk for a future non-correctable error.
When a correctable error occurs, ESM group 1, channel 40 will be set. In the suggested flow chart shown
in
below, the single bit error is determined by directly reading the eFuse error status register,
and not depending on the integrity of the connections between the eFuse controller and the ESM.
38.3.2.4 Stuck at Zero Test
The purpose of the stuck at zero test is to verify that the eFuse controller could signal the ESM if an
autoload error did occur. It basically verifies the path through the eFuse controller and to the ESM. This is
done by writing a special instruction to the eFuse controller boundary register, then verifying that the
proper bits are set in the eFuse controller pins register. Upon successful completion of this test ESM
group 1 channel 41 and ESM group 3 channel 1 will be set. This will force the ERROR pin low.
•
Version A
–
Write boundary register (address 0xFFF8C01C) with 0x003FC000 to set the error signals.
–
Read pins register (address 0xFFF8C02C) and verify that bits 14, 12, 11 and 10 are set.
–
Write boundary register (address 0xFFF8C01C) with 0x003C0000, to clear the error signals.
–
Verify that ESM group 1 channel 41 and group 3 channel 1 are set, then clear them.
If the system cannot support a test which causes the ERROR pin to go low, then the stuck at zero test can
be modified as follows:
•
Version B
–
Write boundary register (address 0xFFF8C01C) with 0x003BC000.
–
Read pins register (address 0xFFF8C02C) and verify that bits 14, 12, and 11 are set.
–
Write boundary register (address 0xFFF8C01C) with 0x003C0000, to clear the error signals.
–
Verify that ESM group 1 channel 41 is set, then clear it.
This alternate method provides less test coverage because the path from the uncorrectable error signal
from the eFuse controller to the ESM is not specifically tested. However, even if this path is broken,
reading the five eFuse error status bits will indicate that an error occurred.
38.3.2.5 eFuse ECC Logic Self Test
The eFuse controller self test performs extensive validation of the ECC logic in the eFuse controller. This
test should only be performed once for every device PORRST cycle. Perform the self test by following
these steps:
•
Write 0x00000258 to the self test cycles register (EFCSTCY) at address 0xFFF8C048.
•
Write 0x5362F97F to the self test signature register (EFCSTSIG) at address 0xFFF8C04C.
•
Write 0x0000200F to the boundary register at address 0xFFF8C01C. This triggers the self test. The
test takes 610 VCLK cycles to complete. The application can poll bit 15 of the pins register at address
0xFFF8C02C to wait for the test to complete.
•
Check ESM group 1 channels 40 and 41 for any errors, neither should be set.
•
Verify that bits 4 to 0 of the eFuse Error Status register at address 0xFFF8C03C are zero.