constant AI_BASE($A450) // $04500000..$04500017 Audio Interface (AI) Base Register constant AI_DRAM_ADDR($00) // $04500000..$04500003 AI: DRAM Address Register constant AI_LEN($04) // $04500004..$04500007 AI: Length Register constant AI_CONTROL($08) // $04500008..$0450000B AI: Control Register constant AI_STATUS($0C) // $0450000C..$0450000F AI: Status Register constant AI_DACRATE($10) // $04500010..$04500013 AI: DAC Sample Period Register constant AI_BITRATE($14) // $04500014..$04500017 AI: Bit Rate Register