# clb-precyinit Fuzzer | |
## PRECYINIT | |
Configures the PRECYINIT mux which provides CARRY4's first carry chain input | |
| PRECYINIT | Value | | |
|------------|---------------------------------| | |
| C0 | Logic 0 | | |
| C1 | Logic 1 | | |
| AX | AX CLB input | | |
| CIN | Carry in from adjacent CLB COUT | | |