An information handing system having apparatus for setting adequate drive
strength based upon direct current (DC) trace resistance uses a
resistance detection traces for each signal layer of a printed circuit
board. These resistance detection traces are coupled to pull-up resistors
and routed with a length and cross-sectional geometry that is
substantially equal to the worst case routing of a net on a bus that is
to be free of receiver mask violations (inadequate received signal
strengths). Reference voltage levels may be determined for each bus so as
to be representative of the minimum voltage acceptable to guarantee that
the worst-case DC trace resistance will not cause the bus waveforms to
fail signal integrity. A voltage comparator circuit may be used to
compare the determined reference voltage levels with the voltage levels
of the resistance detection traces of each of the printed circuit board
layers. When the voltage comparator determines that a resistance
detection trace voltage is too low, an output from the voltage comparator
may be used to generate an error message to a general purpose
input-output (GPIO) that may initiate programming (e.g., change the flash
memory) of a bus controller so as to use the next higher drive strength
setting.