3.4 Interrupt Status Register, RNG_ISR

The RNG_ISR register returns the status of the interrupts.

If the corresponding RNG_IMR bit is unmasked, then an interrupt is generated.

The following table lists the RNG_ISR bit assignments.

Table 3-4 RNG_ISR

Bits Name Description
[31:4] - Reserved.
[3] VN_ERR

When set to 1 it indicates a Von Neumann error.

A Von Neumann error occurs if 32 consecutive collected bits are identical, that is, 32 zeros or 32 ones.

[2] CRNGT_ERR

When set to 1, it indicates a Continuous Random Number Generation Testing (CRNGT) error in the TRNG test failed.

Failure occurs when two consecutive blocks of 16 collected bits are equal.

[1] AUTOCORR_ERR

When set to 1, it indicates that the Autocorrelation test failed four times in a row.

When set, the TRNG stops functioning until the next reset.

[0] EHR_VALID Set to 1 when 192 bits have been collected in the TRNG, and the EHR_DATA[0, 1, 2,…5] registers are ready to be read.
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