nx_robot_signal.nx

nx_robot_signal.nx -- SOVEREIGN hardware SIGNAL/REGISTER rung (the lowest robot-control layer, beneath the driver). A real stepper driver chip (A4988/DRV8825 class) does NOT consume an integer "output" -- it consumes a STEP/DIR digital WAVEFORM on GPIO pins: a rising edge on STEP = one motor micro-step, DIR level = direction. A servo/ESC consumes a PWM bit pattern. This rung MODELS the GPIO register and GENERATES those actual signals from the pulse plan (nx_robot_step, the rung above feeds DOWN into this one) -- building from the hardware rung up. 100% Nishi, integer-only. NEVER-BRICK (#26) BY CONSTRUCTION at the register level: * a write to a NON-allowed pin is REJECTED (can't poke arbitrary hardware registers); * a pin level is normalized to {0,1} (can't write a garbage register value); * PWM duty is clamped to [0, PERIOD] (can't command an out-of-range / >100% pulse). GPIO modeled as arrays (pins[bit]=level, allowed[bit]=writable?) = a faithful register model with no undefined bit-twiddling. Binding pins[] to a real board's MMIO base address is the bench step. license_tier: ORIGINAL expect_exit: 0