intent/pull-up-reach-declared

Remedy ¶

Correct the net name in the declaration to the design’s exact spelling, or remove the entry. A reach declared on a net the design lacks leaves the bus it meant to name held to the default of 3.

What it means ¶

A design’s intent can declare a pull-up reach on a net. The reach tells i2c-pull-up, the two pull-up count rules and the profile pull-up requirements how many series resistors the walk from that net may cross before it reaches a rail. This rule checks each such declaration against the design. It fails when the declared net name is not a net of the design.

intent:
  nets:
    SDA_MAIN: {pull_up_reach_hops: 4}   # isolation resistor, then a level-shifting stage

Why engineers want it ¶

The reach is looked up by the net’s exact name, so a declaration spelled SDA-MAIN on a board whose net is SDA_MAIN matches nothing. Without this rule the walk would quietly keep the default of 3, the bus would still fail i2c-pull-up, and the declaration would read as one that took effect but did not help.

Impact ¶

A misspelled or stale declaration misses the bus it meant to name, and that bus is held to the default reach. The designer placed a pull-up deliberately behind a deeper series network, and that pull-up then reads as missing. The declaration was meant to explain it and is silent about why.

Scope note ¶

It confirms that the net exists and nothing more. Suppose a reach is declared on a real net that no pull-up rule considers, such as a net that is neither I2C nor a profile signal. That declaration changes nothing and still passes here. An undeclared net keeps the default of 3, so a design with no pull_up_reach_hops is checked exactly as before.