REQ-FW-003 — 8-Channel PWM Duty Measurement (ADC)

The firmware shall measure PWM duty on each of 8 channels via the RC-filtered analog inputs (PWM_n_ADC → A0–A7), with a global PWM-load enable (~PWM_EN, D4, active-low). PWM frequency is not measured (no HW edge tap on this rev). See [[E-006]].

For each of the 8 channels, with the DUT PWM active and the load enabled, PWM? <ch> returns a duty proportional to the RC-filtered node voltage (full scale calibrated at bring-up); duty reads ≈0% with PWM/fan-power absent. Numeric pass limits are derived at bring-up (see TC-FW-006).