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Guild: wafer.space Community
Channel: Information / tinytapeout / tinyQV LVS errors
After: 10/31/2025 23:59
Before: 12/01/2025 00:00
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[11/23/2025 18:40] bailey8889



[11/23/2025 18:40] bailey8889
@RebelMike For some reason, netgen is thinking that flattening these cells will make a better match
```
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__mux2_2 in cell tt_um_MichaelBell_tinyQV (0) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__mux2_2 in cell tt_um_MichaelBell_tinyQV (1) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__aoi21_4 in cell tt_um_MichaelBell_tinyQV (0) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__aoi21_4 in cell tt_um_MichaelBell_tinyQV (1) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__nand2_1 in cell tt_um_MichaelBell_tinyQV (0) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__nand2_1 in cell tt_um_MichaelBell_tinyQV (1) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__nand2_4 in cell tt_um_MichaelBell_tinyQV (0) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__nand2_4 in cell tt_um_MichaelBell_tinyQV (1) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__oai21_2 in cell tt_um_MichaelBell_tinyQV (0) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__oai21_2 in cell tt_um_MichaelBell_tinyQV (1) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__oai21_4 in cell tt_um_MichaelBell_tinyQV (0) makes a better match
Flattening instances of gf180mcu_fd_sc_mcu7t5v0__oai21_4 in cell tt_um_MichaelBell_tinyQV (1) makes a better match
```


[11/23/2025 18:42] bailey8889
However, flattening the abstract lef views that don't contain any devices causes a device mismatch.
```
gf180mcu_fd_sc_mcu7t5v0__and3_4 (1)        |gf180mcu_fd_sc_mcu7t5v0__and3_4 (1)
(no matching element)                      |nfet_06v0 (12656->10959)
(no matching element)                      |pfet_06v0 (12656->10745)
Number of devices: 17150 **Mismatch**      |Number of devices: 38854 **Mismatch**
Number of nets: 20323 **Mismatch**         |Number of nets: 28705 **Mismatch**        
```


[11/23/2025 18:43] bailey8889
As to why netgen wants to flatten those cells, there may be a clue in `62-magic-spiceextraction/magic-spiceextraction.log`
```
Warning: use i_peripherals.i_user_peri06.cordic_module.iter_stage.z\[0\]_gf180mcu_fd_sc_mcu7t5v0__dffq_1_Q_D_gf180mcu_fd_sc_mcu7t5v0__clkinv_1_ZN_I_gf180mcu_fd_sc_mcu7t5v0__oai211_1_ZN_B_gf180mcu_fd_sc_mcu7t5v0__oai221_1_ZN_A1_gf180mcu_fd_sc_mcu7t5v0__aoi21_1_ZN_A2_gf180mcu_fd_sc_mcu7t5v0__mux2_2_Z_I0_gf180mcu_fd_sc_mcu7t5v0__mux2_2_Z_I0_gf180mcu_fd_sc_mcu7t5v0__mux2_2_Z_I1_gf180mcu_fd_sc_mcu7t5v0__mux2_2_I0_Z_gf180mcu_fd_sc_mcu7t5v0__nand2_1_A2_ZN_gf180mcu_fd_sc_mcu7t5v0__oai21_1_B_ZN_gf180mcu_fd_sc_mcu7t5v0__mux2_2_I appears more than once in def!
Warning: use i_peripherals.i_user_peri06.cordic_module.iter_stage.z\[0\]_gf180mcu_fd_sc_mcu7t5v0__dffq_1_Q_D_gf180mcu_fd_sc_mcu7t5v0__clkinv_1_ZN_I_gf180mcu_fd_sc_mcu7t5v0__oai211_1_ZN_B_gf180mcu_fd_sc_mcu7t5v0__oai221_1_ZN_A1_gf180mcu_fd_sc_mcu7t5v0__aoi21_1_ZN_A2_gf180mcu_fd_sc_mcu7t5v0__mux2_2_Z_I1_gf180mcu_fd_sc_mcu7t5v0__mux2_2_Z_I1_gf180mcu_fd_sc_mcu7t5v0__mux2_2_Z_I1_gf180mcu_fd_sc_mcu7t5v0__mux2_2_I0_Z_gf180mcu_fd_sc_mcu7t5v0__nand2_1_A2_ZN_gf180mcu_fd_sc_mcu7t5v0__oai21_1_B_ZN_gf180mcu_fd_sc_mcu7t5v0__oai21_1_ appears more than once in def!
...
```


[11/23/2025 18:44] bailey8889
I don't know why yosys is generating such long instance names, but that is what I'd suggest someone looking into.


[11/23/2025 19:06] bailey8889
Changed the channel name: tinyQV LVS errors


[11/23/2025 19:17] bailey8889
Actually, I think magic is truncating the def instance names at around 511 bytes. @Tim Edwards


[11/23/2025 19:21] bailey8889
I found this in the magic repo that looks suspicious.
```
./lef/defRead.c:    char usename[512];
```


[11/23/2025 20:30] bailey8889
Looks like there's already a PR to fix this.

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[11/23/2025 22:09] rtimothyedwards_19428
And I just merged the PR.  It will be available on github in about 10 hours, or you can get the update now from opencircuitdesign.com.

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