-- Sweep the PPI's port C -- which is where the X68000 puts ADPCM pan and the
-- chip's clock divider -- and feed a loud burst under each value, so that the
-- WAV says which value un-mutes the chip. Nothing here is assumed: the segment
-- boundaries are printed and the analysis reads the wave against them.
M = manager.machine
local sp = M.devices[":maincpu"].spaces["program"]
local CTRL, DATA, PPIC = 0xE92001, 0xE92003, 0xE9A005
local SEG = 40            -- host frames per segment
local n = 0
SUB = emu.add_machine_frame_notifier(function()
  n = n + 1
  if n <= 20 then return end
  local k = n - 20
  local seg = math.floor((k - 1) / SEG)
  local off = (k - 1) % SEG
  if seg > 15 then print("[AD] done"); M:exit(); return end
  if off == 0 then
    sp:write_u8(PPIC, seg)
    sp:write_u8(CTRL, 1)
    print(string.format("[AD] seg %2d portC=$%02X starts at host frame %d", seg, seg, n))
  elseif off <= 30 then
    sp:write_u8(DATA, 0x77)          -- two loud positive nibbles
  end
end)