I've been dealing with some different f1spirit.rom dumps lately. One of these dumps surprised me reading MISSION instead of GEAR on the label above the connected gear indicator, while playing.
Is there an official f1spirit.rom dump? Why "mission" ? I never realized that in the past...
I recently had a chat with someone about this, what the difference was and so on.
he told me that according to goodmsx 1.0.999.2:
F-1 Spirit (Konami) (Japan) (1987).rom = F-1 spirit with gear
Thevvie: F-1 Spirit (Konami) (Japan) (1987) [a1].rom = F-1 spirit with mission
Not sure if it changed in later versions of GoodMSX.
And since it's a did you know... well here's also the online password generator 
http://www.cheatmsx.com/en/password_generators/2071/konami-1...
Only found out last year:
The Sony HB-F9P (and -S) is actually a 2-CPU machine!!! 
That is NOT counting obvious suspects like the VDP or S1985 as 'co-processor'. Never knew this for a machine that I've owned for so long & used so often back in the day.
For those interested in puzzles, I'll give you guys some time to find this out yourself. Only 1 hint: you could say it IS documented in the service manual. Just very easy to overlook. And it requires an open mind regarding the strange places you can sometimes find a CPU, or what exotic functions it may perform.
Ah, the OKI chip. 
It's not uncommon to see MCUs in (home)computers eg. as keyboard controller, but this one is odd.
Yes IC28 (OKI MSM6411, a 4-bit 
microcontroller). It's used to initialize IC27, a CX7925B which according to the only single-page doc I was able to find, is a "Serial Input PLL Frequency Synthesizer and Programmable divider". The Wiki page gives a better overview for what a PLL does & typical applications than I could give here.
Funny thing is, this ucontroller's job could have been performed by the Z80 by hooking the relevant pins of IC27 to some I/O port and have the Z80 bit-bang that. Why Sony didn't? Maybe they didn't want to mess with the system ROMs for this. Maybe a dedicated ucontroller was easier to implement than have the Z80 do it & implement such ROM modifications. Maybe they tried, but couldn't fit the code in the ROM block where they wanted it. Who knows...
Also note that this ucontroller's ROM is mask ROM, as in: Sony will have used some kind of (expensive) in-circuit hardware emulator system, developed the code until it was to their liking, and then production IC's were manufactured with that code 'hard-wired' into the silicon. Only worth the trouble when lots & lots of those ucontrollers are produced which all have the same fixed function.
These days, I don't think 4-bit ucontrollers are used any more. Afaik even the simplest "deeply embedded" system like a TV remote, bicycle computer, pocket calculator, etc, etc will use some 8-bit ucontroller at least (8051 family comes to mind, but also Atmel AVR, PIC, and many many others).
