---
page_id: wsd-cts-error-with-split-voltage-io-cells-57205206
type: context-page
schema_version: 1
template_id: discord-page
template_version: template-0.1.0
title: "Thread: CTS error with split voltage IO cells"
slug: wsd-cts-error-with-split-voltage-io-cells-57205206
route: /evidence/designing/project-template/threads/cts-error-with-split-voltage-io-cells
section: reference
access: public
summary: 5 Discord messages from 📐 - Designing/📝-project-template/threads/cts-error-with-split-voltage-io-cells.md.
status: published
asset_base: .
home_href: /
md_url: /evidence/designing/project-template/threads/cts-error-with-split-voltage-io-cells.md
toc_enabled: true
talk_enabled: false
agent_view_enabled: true
copy_buttons_enabled: true
footer_enabled: true
search_indexed: true
tags: [discord, wafer-space, archive]
last_updated: 2026-08-19
talk_url: /evidence/designing/project-template/threads/cts-error-with-split-voltage-io-cells.talk.md
talk_route: /evidence/designing/project-template/threads/cts-error-with-split-voltage-io-cells/talk
---
# Thread: CTS error with split voltage IO cells
Category: **📐 - Designing**
Parent channel: **#📝-project-template**
Thread ID: `1513112664635867288`
Messages: **5**
## message-1513112673695301723
**2026-06-07T09:29:33.683+00:00 — RebelMike (@rebelmike)**
- Message ID: `1513112673695301723`
- Author ID: `691780627338625077`
- Nickname: RebelMike
- User name: rebelmike
- Type: `Default`
- Discord message: https://discord.com/channels/1361349522684510449/1513112664635867288/1513112673695301723
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%93%90%20-%20Designing/%F0%9F%93%9D-project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
**Content**
````text
When trying to use the ocd version of the IO cells, I see this error in CTS:
```
[INFO CTS-0007] Net "clk_PAD2CORE" found for clock "clk_PAD".
[INFO CTS-0122] Clock net "clk_PAD2CORE" is skipped for CTS because it is not connected to any output instance pin or input block terminal.
[WARNING CTS-0083] No clock nets have been found.
[INFO CTS-0008] TritonCTS found 0 clock nets.
[WARNING CTS-0082] No valid clock nets in the design.
```
I've confirmed it happens on the default template too. There it doesn't cause the build to fail - presumably the tooling can cope without needing a clock tree for a small number of registers, but it's obviously bad, and in a larger design it does cause failures.
````
Other message metadata
```json
{
"author": {
"avatarUrl": "2026-06_media/49aaff687e56f04e7bbdedf0077bab75-7DDB4.png",
"discriminator": "0000",
"isBot": false
},
"message": {}
}
```
---
## message-1513116323670917251
**2026-06-07T09:44:03.905+00:00 — Leo Moser (mole99) (@mole99)**
- Message ID: `1513116323670917251`
- Author ID: `323371864074485771`
- Nickname: Leo Moser (mole99)
- User name: mole99
- Type: `Default`
- Discord message: https://discord.com/channels/1361349522684510449/1513112664635867288/1513116323670917251
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%93%90%20-%20Designing/%F0%9F%93%9D-project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
**Content**
```text
Can confirm, that is not a nice clock tree. (I'm also wondering why I don't see the SPEF delays here.)
```
**Attachments**
- Resolved media URL: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06_media/Bildschirmfoto_vom_2026-06-07_11-40-26-E7A56.png
Attachments data
```json
[
{
"fileName": "Bildschirmfoto_vom_2026-06-07_11-40-26.png",
"fileSizeBytes": 307782,
"id": "1513116323700543608",
"url": "2026-06_media/Bildschirmfoto_vom_2026-06-07_11-40-26-E7A56.png"
}
]
```
Other message metadata
```json
{
"author": {
"avatarUrl": "2026-06_media/3c7c17f3225f6e56f4dccd83f14383f2-73F83.png",
"discriminator": "0000",
"isBot": false,
"roles": [
{
"color": null,
"id": "1423020172595298314",
"name": "Mod",
"position": 4
}
]
},
"message": {}
}
```
---
## message-1513116488989413526
**2026-06-07T09:44:43.32+00:00 — Leo Moser (mole99) (@mole99)**
- Message ID: `1513116488989413526`
- Author ID: `323371864074485771`
- Nickname: Leo Moser (mole99)
- User name: mole99
- Type: `Default`
- Discord message: https://discord.com/channels/1361349522684510449/1513112664635867288/1513116488989413526
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%93%90%20-%20Designing/%F0%9F%93%9D-project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
**Content**
```text
I'll compare the LEF/LIB views of the OCD cells with the foundry ones.
```
Other message metadata
```json
{
"author": {
"avatarUrl": "2026-06_media/3c7c17f3225f6e56f4dccd83f14383f2-73F83.png",
"discriminator": "0000",
"isBot": false,
"roles": [
{
"color": null,
"id": "1423020172595298314",
"name": "Mod",
"position": 4
}
]
},
"message": {}
}
```
---
## message-1513119181040779364
**2026-06-07T09:55:25.155+00:00 — Leo Moser (mole99) (@mole99)**
- Message ID: `1513119181040779364`
- Author ID: `323371864074485771`
- Nickname: Leo Moser (mole99)
- User name: mole99
- Type: `Default`
- Discord message: https://discord.com/channels/1361349522684510449/1513112664635867288/1513119181040779364
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%93%90%20-%20Designing/%F0%9F%93%9D-project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
**Content**
```text
Found the issue: `PIN Y` in the LEF does not have a direction set, making it `INPUT` by default.
You can edit `libs.ref/gf180mcu_ocd_io/lef/gf180mcu_ocd_io.lef` and add `DIRECTION OUTPUT ;` after line 3432.
```
**Reactions**
- Resolved media URL: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06_media/1f44d-27259.svg
- Resolved media URL: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06_media/49aaff687e56f04e7bbdedf0077bab75-7DDB4.png
Reactions data
```json
[
{
"count": 1,
"emoji": {
"code": "thumbsup",
"id": "",
"imageUrl": "2026-06_media/1f44d-27259.svg",
"isAnimated": false,
"name": "👍"
},
"users": [
{
"avatarUrl": "2026-06_media/49aaff687e56f04e7bbdedf0077bab75-7DDB4.png",
"color": null,
"discriminator": "0000",
"id": "691780627338625077",
"isBot": false,
"name": "rebelmike",
"nickname": "RebelMike"
}
]
}
]
```
Other message metadata
```json
{
"author": {
"avatarUrl": "2026-06_media/3c7c17f3225f6e56f4dccd83f14383f2-73F83.png",
"discriminator": "0000",
"isBot": false,
"roles": [
{
"color": null,
"id": "1423020172595298314",
"name": "Mod",
"position": 4
}
]
},
"message": {}
}
```
---
## message-1513119322644680815
**2026-06-07T09:55:58.916+00:00 — Leo Moser (mole99) (@mole99)**
- Message ID: `1513119322644680815`
- Author ID: `323371864074485771`
- Nickname: Leo Moser (mole99)
- User name: mole99
- Type: `Default`
- Discord message: https://discord.com/channels/1361349522684510449/1513112664635867288/1513119322644680815
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
- Archive source: https://discord.wafer.space/wafer-space/%F0%9F%93%90%20-%20Designing/%F0%9F%93%9D-project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06.json
**Content**
```text
Thanks for the report, Mike! I'll make sure the PDK is updated accordingly.
```
**Reactions**
- Resolved media URL: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06_media/1f49c-71A75.svg
- Resolved media URL: https://discord.wafer.space/wafer-space/%F0%9F%8F%97%EF%B8%8F%20-%20Designing/project-template/cts-error-with-split-voltage-io-cells/2026-06/2026-06_media/49aaff687e56f04e7bbdedf0077bab75-7DDB4.png
Reactions data
```json
[
{
"count": 1,
"emoji": {
"code": "purple_heart",
"id": "",
"imageUrl": "2026-06_media/1f49c-71A75.svg",
"isAnimated": false,
"name": "💜"
},
"users": [
{
"avatarUrl": "2026-06_media/49aaff687e56f04e7bbdedf0077bab75-7DDB4.png",
"color": null,
"discriminator": "0000",
"id": "691780627338625077",
"isBot": false,
"name": "rebelmike",
"nickname": "RebelMike"
}
]
}
]
```
Other message metadata
```json
{
"author": {
"avatarUrl": "2026-06_media/3c7c17f3225f6e56f4dccd83f14383f2-73F83.png",
"discriminator": "0000",
"isBot": false,
"roles": [
{
"color": null,
"id": "1423020172595298314",
"name": "Mod",
"position": 4
}
]
},
"message": {}
}
```
---