(version 1)

# hbox-watchdog v4 — design rules
#
# Why three rules instead of one blanket minimum:
#
# The old file was a single unconditional (min 0.15mm).  A custom rule outranks
# the netclass table, and an unconditional rule matches EVERY pair on the board,
# so it was silently overriding the HV24 netclass's 0.5 mm clearance everywhere.
# The netclass said 0.5; DRC was only ever enforcing 0.15.
#
# These three are mutually exclusive on the case that matters, so they give the
# same answer whether KiCad resolves by rule order or by specificity:
#
#   1. neither item is HV24                       -> 0.15 mm  (unchanged)
#   2. either item is HV24                        -> 0.50 mm
#   3. except U2 pad-to-pad, its own land pattern -> 0.15 mm
#
# Rule 3 exists for exactly one pair.  U2 is the MP1584EN buck (SOIC-8-EP):
# pad 7 (24V, 1.95 x 0.6) to pad 9 (the 2.29 x 3.0 exposed thermal pad, GND) is
# 0.355 mm, and that is the manufacturer's qualified land pattern — it is set by
# the package, not by routing, so no amount of rerouting can open it.  Scoping
# the exception to Pad-to-Pad inside U2 keeps it from relaxing anything else:
# measured on this board, U2's courtyard contains 9 pads and all 9 belong to U2,
# so this condition cannot match a foreign pad.  The tracks and vias that pass
# through that courtyard are excluded by the A.Type/B.Type test and stay at the
# full 0.5 mm.
#
# HV24 = /24V_IN, 24V, IGN_IN, Q10_GATE  (netclass_patterns in the .kicad_pro)
#
# Note: raising HV24 to 0.5 mm also widens the copper pour pullback around those
# nets, because a zone floods to max(its own clearance, the effective DRC
# clearance) — 0.3 mm before, 0.5 mm now.  Press B to refill before running DRC.

(rule "Minimum clearance 1"
	(constraint clearance (min 0.15mm))
	(condition "A.NetClass != 'HV24' && B.NetClass != 'HV24'")
)

(rule "HV24 clearance"
	(constraint clearance (min 0.5mm))
	(condition "(A.NetClass == 'HV24' || B.NetClass == 'HV24') && !(A.Type == 'Pad' && B.Type == 'Pad' && A.memberOfFootprint('U2') && B.memberOfFootprint('U2'))")
)

(rule "HV24 exception: MP1584EN land pattern"
	(constraint clearance (min 0.15mm))
	(condition "A.Type == 'Pad' && B.Type == 'Pad' && A.memberOfFootprint('U2') && B.memberOfFootprint('U2')")
)