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Memory Map

The following is a memory map that was generated based on the MAME source code (.180).  This information is only as accurate as the MAME driver is.  If you see any errors, please let me know what that error is.
 
The Memory Area is related to where the information is from (CPU, Sound Board, etc..), and it may also reflect what it has in common with other hardware.
Omega Race (Midway, 1981)
Memory Area:main_map
Address RangeLengthFunctionDescription
0x0000-0x3FFF16384ROM
0x4000-0x4BFF3072RAM
0x5C00-0x5CFF256RAM, Sharednvram (/* NVRAM */)
0x8000-0x8FFF4096RAM, Shared, Regionvectorram, maincpu, 0x8000 (/* vector ram */)
0x9000-0x9FFF4096ROM(/* vector rom */)
Memory Area:port_map
Address RangeLengthFunctionDescription
0x00081Readomegrace_vg_go_r
0x00091Device Readwatchdog, watchdog_timer_device, reset_r
0x000A1Device Writedvg, dvg_device, reset_w
0x000B1Read PortAVGDVG (/* vg_halt */)
0x0080SpecialActive Low
0x00101Read PortDSW1 (/* DIP SW C4 */)
0x000040kActive High
0x000150kActive High
0x000270kActive High
0x0003100kActive High
0x0000150k 250kActive High
0x0004250k 500kActive High
0x0008500k 750kActive High
0x000c750k 1500kActive High
0x00001C/2S 2C/4SActive High
0x00101C/2S 2C/5SActive High
0x00201C/3S 2C/6SActive High
0x00301C/3S 2C/7SActive High
0x0040UnusedActive High
0x0000OffActive High
0x0040OnActive High
0x0080UnusedActive High
0x0000OffActive High
0x0080OnActive High
0x00111Read PortIN0 (/* Player 1 input */)
0x0001Coin 1Active Low
0x0002Coin 2Active Low
0x0004UnknownActive Low
0x0008UnknownActive Low
0x0010TiltActive Low
0x0020Button 2Active Low
0x0040Button 1Active Low
0x00121Read PortIN1 (/* Player 2 input */)
0x0001Button 2Active Low
0x0002Button 1Active Low
0x00042 Players Start (1 creditActive High
0x00082 Players Start (2 creditsActive High
0x0010UnknownActive Low
0x0020UnknownActive Low
0x00401 Player Start (1 creditActive High
0x00801 Player Start (2 creditsActive High
0x00131Writeomegrace_leds_w (/* coin counters, leds, flip screen */)
0x00141Writeomegrace_soundlatch_w (/* Sound command */)
0x00151Readomegrace_spinner1_r (/* 1st controller */)
0x00161Read PortSPIN1 (/* 2nd controller (cocktail) */)
0x003fDialActive High
0x00171Read PortDSW2 (/* DIP SW C6 */)
0x0007Coin_AActive High
0x00062C_1CActive High
0x00071C_1CActive High
0x00034C_5CActive High
0x00043C_4CActive High
0x00052C_3CActive High
0x00001C_2CActive High
0x00011C_3CActive High
0x00021C_5CActive High
0x0038Coin_BActive High
0x00302C_1CActive High
0x00381C_1CActive High
0x00184C_5CActive High
0x00203C_4CActive High
0x00282C_3CActive High
0x00001C_2CActive High
0x00081C_3CActive High
0x00101C_5CActive High
0x0040Free_PlayActive High
0x0000OffActive High
0x0040OnActive High
0x0080CabinetActive High
0x0000UprightActive High
0x0080CocktailActive High
Memory Area:sound_map
Address RangeLengthFunctionDescription
0x0000-0x07FF2048ROM, Mirror0x800
0x1000-0x13FF1024RAM
Memory Area:sound_port
Address RangeLengthFunctionDescription
0x00001Device Readsoundlatch, generic_latch_8_device, read (// the game reads from ay1 port b, but ay8912 only has port a)
0x0000-0x00012Device Writeay1, ay8912_device, address_data_w
0x0002-0x00032Device Writeay2, ay8912_device, address_data_w
 

ROM Map for this game

 
This is the ROM map for the game.  This should tell you what address the ROM is at, how big it is, what it's used for.   
Memory Area:audiocpu
Address RangeLengthLabel/LocationDescription
0x0000-0x07FF2048sound.k5CRC(7d426017) (Fluke: 7D72)
Memory Area:maincpu
Address RangeLengthLabel/LocationDescription
0x0000-0x0FFF4096omega.m7CRC(0424d46e) (Fluke: 9B58)
0x1000-0x1FFF4096omega.l7CRC(edcd7a7d) (Fluke: 57EE)
0x2000-0x2FFF4096omega.k7CRC(6d10f197) (Fluke: 3F07)
0x3000-0x3FFF4096omega.j7CRC(8e8d4b54) (Fluke: 4B6C)
0x9000-0x97FF2048omega.e1CRC(1d0fdf3a) (Fluke: 286F)
0x9800-0x9FFF2048omega.f1CRC(d44c0814) (Fluke: A9F1)
Memory Area:user1
Address RangeLengthLabel/LocationDescription
0x0000-0x00FF256dvgprom.binCRC(d481e958) (Fluke: F02C)
0x0000-0x00FF256dvgprom.binCRC(d481e958) (Fluke: F02C)
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