[otbn,doc] Stop calling URND an LFSR
The new implementation isn't one.
Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/hw/ip/otbn/doc/_index.md b/hw/ip/otbn/doc/_index.md
index 18c4493..737a4a8 100644
--- a/hw/ip/otbn/doc/_index.md
+++ b/hw/ip/otbn/doc/_index.md
@@ -286,7 +286,7 @@
Intended for use in masking and blinding schemes.
Use RND for high-quality randomness.
-The number is sourced from an LFSR.
+The number is sourced from an local PRNG.
Reads never stall.
</td>
</tr>
@@ -362,7 +362,7 @@
Intended for use in masking and blinding schemes.
Use RND for high-quality randomness.
-The number is sourced from an LFSR.
+The number is sourced from a local PRNG.
Reads never stall.
</td>
</tr>
@@ -525,10 +525,10 @@
`RND` CSR reads get bottom 32b and simply discard the other 192b on a read.
When stalling on an `RND` read, OTBN will unstall on the cycle after it receives WLEN RND data from the EDN.
-`URND` provides bits from an LFSR within OTBN; reads from it never stall.
+`URND` provides bits from an local PRNG within OTBN; reads from it never stall.
The `URND` LFSR is seeded once from the EDN connected via `edn_urnd` when OTBN starts execution.
-Each new execution of OTBN will reseed the `URND` LFSR.
-The LFSR state is advanced every cycle when OTBN is running.
+Each new execution of OTBN will reseed the `URND` PRNG.
+The PRNG state is advanced every cycle when OTBN is running.
### Operational States {#design-details-operational-states}
