FS-A1 pal patched and MSX2+ upgrade!

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By vossi

Rookie (24)

vossi's picture

01-04-2016, 09:26

Hi,
I just bought a japanese FS-A1 with 110V/NTSC.

The ROM is stored in a 128kB mask-Rom with 28 Pins.
I have patched the timer constant in the Basic/Bios to 50Hz and changed the 9938 init in the ext.Rom to PAL (Reg 09 Bit #1)
I burned the ROM in a 27c010 and plugged it with an 32/28 pin Adapter in the Panasonic. Now I have a great RGB-signal with PAL on my Thomson-Monitor ;-)

Than I changed the 9938 to a 9958 (with wiring pin 4,21,27) - and it works!

At last I modified the FS-A1FX MSX2+ Rom (without Kanji) to PAL and burned it in an eprom, but I have only a black Screen!

Is it possible to put every msx2+ ROM in every msx2/msx2+ machine?
Or is the Rom adapted to every Special machine (gate Array/msx2-engine)???
Is there standard-msx2+ Basic 3 that works in my machine?

greets
Christian

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By gdx

Prophet (3083)

gdx's picture

01-04-2016, 10:52

vossi wrote:

I burned the ROM in a 27c010 and plugged it with an 32/28 pin Adapter in the Panasonic. Now I have a great RGB-signal with PAL on my Thomson-Monitor ;-)

The order Main-Rom + Sub-ROM + Firmware is it right?

By vossi

Rookie (24)

vossi's picture

01-04-2016, 11:06

Yes its in the correct order and the mapping is the same as in the fsa1.
In the rom is at 0000 the basic, at 8000 the ext.rom, at 10000 the diskrom, at 18000 the Panasonic cockpit.
First I tried only basic+ext. Basic, but it doesn't worked.

Should a msx2+ rom of an other computer generally work???

By gdx

Prophet (3083)

gdx's picture

01-04-2016, 11:30

vossi wrote:

At last I modified the FS-A1FX MSX2+ Rom (without Kanji) to PAL and burned it in an eprom, but I have only a black Screen!

Perhaps because of the F4H port I/O or something missing.

By vossi

Rookie (24)

vossi's picture

01-04-2016, 11:55

I thought the f4 port is not necessary?

It's only needed to prevent the intro at a softboot.

By gdx

Prophet (3083)

gdx's picture

01-04-2016, 12:10

Yes, it is to differentiate the soft reset from hard reset. Without the F4 port the hard reset is missing.

By vossi

Rookie (24)

vossi's picture

01-04-2016, 17:41

I tried the patched MSX2+-ROM from HansOranje for the NMS8250.
This works in my Panasonic, but without Intro - maybe because of the missing F4-register.
But the keyboard layout is different to my japanese fs-a1

By Alexey

Guardian (2444)

Alexey's picture

03-04-2016, 15:19

You can easily add F4 port to your computer by installing this board on top of the z80 processor. The board has been verified to work correctly.

By madscient

Master (179)

madscient's picture

15-04-2016, 07:04

F4 register allows to distinguish whether soft reset or hard reset.
This feature is fix for device enabler issue which is spec fault of MSX2.

Device enabler issue is; the system disables internal device when same external device was detected on booting.
But in case of soft reset, system misidentifies existing internal device as external one, then internal device is disabled.
Typically this issue appeared for Kanji ROM device.
On the MSX2 computer contains Kanji ROM, internal Kanji will never function after soft reset.

By Grauw

Ascended (8508)

Grauw's picture

15-04-2016, 09:31

Interesting! I always wondered.

By vossi

Rookie (24)

vossi's picture

15-04-2016, 09:46

Thanks for the Info, madscient.

I wrote a small GAL-logic for the F4-latch and the OPLL-address-select.
This replaces 6 TTL-Chips !!!
I will test it in my NMS8255:

Title MSX2+ F4-Latch+OPLL-Combo
Pattern A0-A7, RQ, RD, WR,D7, VCRST, IOF4, WRF4
Revision 0.1
Auther Ceffy
Date 06.04.2016

; VCRST Generation:
; ---|<|--- 10µF
; | | +
; +5V -----4,7k------VCRST----||----GND

CHIP F4OPLL GAL22V10 ; Device definition

; / NOT or active-low
; * AND
; + OR
; = Combinational output
; := Registered output

; Pin definition
;1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
A0 A1 A2 A3 A4 A5 A6 A7 IORQ RD WR GND

;13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24]
D7 VCRST IOF4 WRF4 F4 IO7A NC NC NC NC NC VCC

EQUATIONS

IOF4 = /A0 * /A1 * A2 * /A3 * A4 * A5 * A6 * /A7 * /IORQ ; CPU IO to Port F4

WRF4 = IOF4 * /WR

/ENF4 = IOF4 * /RD ; Enable Tristate-Buffer (74LS125) to D7

F4 = WRF4 * D7 ; F4-Latch (to 74LS125 input)
+ /WRF4 * F4
+ /VCRST ; VCRST = LO at power on

IO7A = /A1 * A2 * A3 * A4 * A5 * A6 * /A7 * IORQ ; CPU IO to Port 7A/7B OPLL

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