Erc Rules

SKiDL ERC Rules

When to use

• Before exporting any netlist
• After any circuit code change
• During design review (errors must be 0 before proceeding)

Procedure

Drive strength order (PWR > OUT > BIDIR > TRI > OC > IN > NC)

Must-fix errors — treat as blockers:

• Output-to-output conflict (two OUT pins on same net)
• Floating input on active IC
• Power pin conflict
• Unconnected pin on IC (unless NC)

Warnings — investigate, suppress only with justification:

• Open-drain needs external pull-up → add resistor or erc_assert()
• Multi-driver bus (I2C, SPI) → expected; suppress with erc_assert()

Mandatory decoupling: Every IC VCC pin → 100 nF minimum, named C_DECOUP_*

Intentional NC:

U1['NC1', 'NC2'] += NC

Warning suppression:

erc_assert("expected open-drain", net)

ERC run pattern:

if __name__ == "__main__":
    # ... circuit ...
    ERC()

Output

Produce this summary line after every ERC run:

"X errors, Y warnings, Z notes. Circuit is [PASS/FAIL]."

Validation

• Never declare a circuit ready until errors == 0
• Suppressed warnings must have a comment explaining why

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: nickkraakman
• Source: nickkraakman/skidl-skills
• License: MIT

Install and usage instructions live in the source repository linked above.