Analog Devices ADSP-SC58 Series Hardware Reference Manual page 3265

Table 47-24: TRNG_TEST Register Fields (Continued)
Bit No.
(Access)
27:16 PATTERN
(R/W)
12:8 SEL
(R/W)
5 RUNPKR
(R/W)
4 CONTPKR
(R/W)
3 NOLFSRFB
(R/W)
ADSP-SC58x/ADSP-2158x SHARC+ Processor Hardware Reference
Bit Name
Test Pattern.
The TRNG_TEST.PATTERN bit field sets up a repeating sequence of bits to be fed
into the selected FRO delay chain TRNG_TEST.PATTFRO =1 and/or the selected
FRO error detection circuit TRNG_TEST.PATTDET =1. This field is rotated right
over one bit, once every sample period, when either of these control bits is 1. There-
fore, bit [16] is the actual pattern bit fed into the test target.
Test Select.
The TRNG_TEST.SEL bit field configures the number of the FRO to be tested, the
value should be in the range of 0 to 7.
Test Run Poker.
When the TRNG_TEST.RUNPKR bit is set, it provides direct access to the inputs of
the Monobit, Run and Poker Test circuits (writing input data in chunks of 32 bits to
the TRNG_INPUT0 register). While this bit is 1, the TRNG is not allowed to gener-
ate entropy but any buffered random data is preserved, to be loaded into the output
registers as soon as this bit is reset to 0 again. The TRNG_STAT.NEEDCLK bit is
forced active while this bit is 1. The Monobit, Run and Poker Test circuits are reset to
their initial states on any change of this bit.
Continue Poker.
When the TRNG_TEST.CONTPKR bit is set, Monobit Test and Poker Test keep run-
ning continuously by not resetting the Monobit count (TRNG_MONOBITCNT) and
poker counters
This bit can only be set to 1 when TRNG_CTL.TSTMODE =1.
No LFSR Feedback.
When the TRNG_TEST.NOLFSRFB bit is set, it removes XNOR feedback from the
main LFSR, converting it into a normal shift register for the XOR-ed outputs of the
FROs (shifting data in on the LSB side). A 1 also forces the LFSR to sample continu-
ously. This bit can only be set to 1 when TRNG_CTL.TSTMODE =1.
Description/Enumeration
(TRNG_POKER[n] register) at the end of each 20,000 bits test block.
0 Do not continue poker test
1 Continue poker test
0 Keep XNOR feedback
1 Remove XNOR feedback
ADSP-SC58x TRNG Register Descriptions
47–37