Did you know..? (MSX trivia!)

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Par tfh

Prophet (3428)

Portrait de tfh

28-03-2017, 18:35

Guillian wrote:
ghost_jp wrote:

Wow!! Would you please show us a video replay?

Here is the video

Shouldn't it be possible to find the data of this in the system ROMs somewhere?

Par Guillian

Prophet (3529)

Portrait de Guillian

28-03-2017, 20:06

@ghost_jp and hamlet: You are welcome!

@tfh: yes, it is a 16K ROM (hb-f1_firmware1.rom) Just load it in an emulator, MegaFlashROM or similar.

Par Hydragon

Paladin (751)

Portrait de Hydragon

28-03-2017, 20:40

friguron wrote:

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 Wink

Par RetroTechie

Paragon (1563)

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09-04-2017, 21:06

Only found out last year:

The Sony HB-F9P (and -S) is actually a 2-CPU machine!!! Shocked! 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.

Par Eugeny_Brychkov

Paragon (1232)

Portrait de Eugeny_Brychkov

10-04-2017, 10:23

RetroTechie wrote:

Only 1 hint: you could say it IS documented in the service manual. Just very easy to overlook.

Looked into the circuit diagram, I would say there could be only one suspect, but I hardly believe it falls under category of


the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. (source)

Update: funny enough I have found this device, and it is not CPU, but it is microcontroller which is having CPU inside it with its ROM, RAM, ALU and I/O.

@RetroTechie, thank you for sharing this information!

Par hap

Paragon (2043)

Portrait de hap

10-04-2017, 19:08

Ah, the OKI chip. Smile It's not uncommon to see MCUs in (home)computers eg. as keyboard controller, but this one is odd.

Par Manuel

Ascended (19678)

Portrait de Manuel

10-04-2017, 20:10

What is it used for in this machine?

Par hap

Paragon (2043)

Portrait de hap

10-04-2017, 20:22

phase control, see HB-F9P service manual schematics IC28. The MCU in question is an OKI MSM6411(4-bit MCU with 1KB internal ROM).

Par RetroTechie

Paragon (1563)

Portrait de RetroTechie

10-04-2017, 22:35

Yes IC28 (OKI MSM6411, a 4-bit Cool 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).

Par Manuel

Ascended (19678)

Portrait de Manuel

11-04-2017, 00:03

OK, but what does it do? What is the function of the microcontroller+PLL in this MSX?

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