05385: downtown: After entering a high score, the high scores are reset to zero

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
05385	Gameplay	Major	Always	Dec 1, 2013, 20:39	Jun 9, 2021, 23:29

Tester	murve33	View Status	Public	Platform
Assigned To	Kale	Resolution	Fixed	OS	Windows Vista/7/8 (64-bit)
Status [?]	Resolved			Driver	seta/seta.cpp
Version	0.151	Fixed in Version	0.233	Build
		Fixed in Git Commit	80cfd04	Github Pull Request #	#8155

Summary	05385: downtown: After entering a high score, the high scores are reset to zero
Description	When the player is prompted to type in their initials, their high score is displayed in the top middle column where it should be. Once the player enters their initials the high score column resets to zero, and all of the high scores display 00. Related glitch: When typing in your initials after a 1-player game, Player-2 is prompted to type in their initials, even though they received a score of zero.
Steps To Reproduce	1. Insert Coin 2. Hit 1-player start 3. Rack up more than 0 points 4. Die 5. Type in player 1, in addition to player 2's initials Then the glitch happens
Additional Information	I've tested all of the clones in MAMEUI64 .145u7 and MAMEUI64 .151, the same thing happens. I've tried typing in player 2's initials before typing in player 1's. The same glitch occurs in a 2-player game as well
Github Commit

Flags
Regression Version
Affected Sets / Systems	downtown

Attached Files

No.18944 Kale Developer Jun 7, 2021, 22:01	https://github.com/mamedev/mame/blob/master/src/mame/drivers/seta.cpp#L12142 Game reads writes to protection area $200111 onward, if initialized in service mode* then default table should be 50k - 40k - 30k - 20k - 10k *which implies that there's an undumped MCU with NVRAM or EEPROM device attached for saving those scores.
No.18947 Robbbert Senior Tester Jun 8, 2021, 02:20	Does this fix it? https://github.com/mamedev/mame/commit/80cfd0464e9c38fb9bc3a74b87300f5d1b018488
No.18948 AJR Developer Jun 8, 2021, 02:59	Downtown's protection/NVRAM IC appears to be a 48-pin DIP marked X1-009 (with a Mitsubishi-style datecode). A lithium battery is located nearby on the PCB. X1-009 also appears on Yumefuda (again with a battery) and Pairs Love (with no battery). I somewhat doubt it's really a MCU.
No.18957 Kale Developer Jun 9, 2021, 22:15 edited on: Jun 9, 2021, 22:16	In DownTown $2000f9 is lock/unlock, similar to $a7fc in yumefuda including writing 0xa3-0x00, except the space doesn't match ($f9 / 2 = $7c) and of course it actually bankswitches "WALTZ0" from $2b8 in the window here. While $200000 seems to be some kind of "keep alive" during POST while doing a main 68k ROM checksum. Pairs Love hookup is similar to DownTown plus connects $900060 to an incrementing counter when credit is inserted. I sense a code smell in the current "cached RAM" handling for the $100-$1ff RAM area, game does a very limited/naive use of the RAM at PC=892c and may just bankswitch again with a ROM (it just checks for value inequality after all) Regardless gonna mark this as resolved, feel free to do a mini-device or open a "Write a X1-009 device" issue on github.