DFF UNSAT

[Dinple]

Hi, thanks for releasing the code.

While using the default setting to generate layouts for ASAP7, I found most of the DFFs show UNSAT and no GDS was generated.

Here is an example output:

place sol : 20
The number of pin for net pd3: 2
The number of pin for net QN: 2
The number of pin for net SS: 3
The number of pin for net clkb: 4
The number of pin for net clkn: 5
The number of pin for net SH: 4
The number of pin for net net020: 2
The number of pin for net MS: 6
The number of pin for net MH: 3
The number of pin for net pd1: 1
The number of pin for net net076: 1
The number of pin for net net079: 1
The number of pin for net pd2: 1
The number of pin for net net077: 1
The number of pin for net net078: 1
The number of pin for net net051: 1
The number of pin for net pu1: 1
The number of pin for net CLK: 1
The number of pin for net D: 1
The number of pin for net RESET: 2
The number of pin for net SET: 2
"./AutoCellGen/MAKE/PLACE_ROUTE/./output/placement/../route/ASYNC_DFFHx1_ASAP7_75t_R_w22_2.txt"
UNSAT!
routing step done!
Routing for solution 3 of width 22

Are there any specific settings I need to turn on for DFF?