# I2C pull-up and rise-time budget
# Scope: RC rise-time and sink-current resistor interval; bus capacitance supplied.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

voltage = 3.3 V
lowVoltage = 0.4 V
sinkCurrent = 3 mA
capacitance = 100 pF
riseTime = 300 ns

minimum := (voltage-lowVoltage)/sinkCurrent [ohm]
maximum := riseTime/(0.8473*capacitance) [ohm]

check resistor interval feasible: maximum >= minimum

scenario alternative: voltage = 2.64 V