mirror of https://github.com/openXC7/prjxray.git
19 lines
639 B
Markdown
19 lines
639 B
Markdown
# CLBn5FFMUX Fuzzer
|
|
|
|
## Purpose
|
|
Document A5FFMUX family of CLB muxes
|
|
|
|
## Algorithm
|
|
5FFMUX
|
|
Inputs can come from either the LUT6_2 NO5 output or the CLB NX input
|
|
To perturb the CLB the smallest, want LUT6 always instantiated
|
|
However, some routing congestion that would require putting FFs in bypass
|
|
(which turns out is actually okay, but didn't realize that at the time)
|
|
Decided instead ot instantiate LUT8, but not use the output
|
|
Turns out this is okay and won't optimize things away
|
|
So then, the 5FF D input is switched between the O5 output and an external CLB input
|
|
|
|
## Outcome
|
|
Bits are one hot encoded per mux position
|
|
|