Wiki editing discussion | MSX Resource Center (Page 183/198)

Enlighted (6449)

06-03-2023, 13:10

Pentarou wrote:

gdx wrote:

Why didn't you just add what's missing in the wiki?

Because it seems that the wiki is owned by 2 people: One writes (without any proof) that the "Nikko" is NTSC then comes the other who writes (again without any proof) that the system is PAL.

Your argument makes no sense because if you were to say what is missing, it would make it possible to decide who is right.

Mars2000 put NTSC because the Nikko computer looks Japanese. and I put PAL because there are inconsistencies and all the computers that use the T7927A are PAL. The wiki is not marble, the errors are corrected as and when the info arrive. If everyone acted like you, there would be nothing in the wiki.

Pentarou wrote:

Why are you mentioning those countries at all?

Because PAL-M v-blank frequency is 60Hz, and if the T7927A do it. It is possible that the Nikko computer can output an NTSC signal. The PAL-M signal can easily be created from an NTSC signal. This is probably what was done for the Brazilian MSX1s.

Par mars2000you

Enlighted (6575)

06-03-2023, 13:38

The fact that the collector/seller is in Europe, not in Japan or USA, is also another element that goes in the PAL direction. Not enough by itself, but being coherent with the other known elements (Use of T927(A) on other MSX machines, katakana or hiragana not printed on keys).

As I've already mentioned it, the dump of the BIOS/BASIC EPROM will give the definitive answer, especially because it's a MSX1, not only for the Kana or Code key, but also for the VDP frequency. As PAL-M was/is only used in Brazil, I think that it will be PAL at 50Hz.

Par Pentarou

Hero (568)

06-03-2023, 21:53

gdx wrote:

Mars2000 put NTSC because the Nikko computer looks Japanese. and I put PAL because there are inconsistencies and all the computers that use the T7927A are PAL. The wiki is not marble, the errors are corrected as and when the info arrive. If everyone acted like you, there would be nothing in the wiki.

Both of you wrote those info without having any concrete proof, moreover Mars2000 did show you that there are PAL and NTSC machines with both T7927 & T7927A.
So according to you it's the correct way to act?

I'm giving you an example of why I think this is wrong:
You (or Mars) wrote: (probably DC 9V, 1.2A with the minus at the center)
Now, I may be blind, but to my eyes it seems the center pin is connected to the red wire, which then goes to the switch and to the regulator, so it is the Positive wire.
I may be wrong, because I can't really see well in the photo...
But if I'm right and someone connects a PSU wired according to the wiki description, then what happens to the machine?

Par Pentarou

Hero (568)

06-03-2023, 22:08

This is about the T7927/A Pinout in the wiki:

mars2000you wrote:

Pinouts are not my speciality, but I think the pins should be ordered in numerical order, so it would be easier to read the table and optionally detect the missing pins in the wiki.

Unfortunately it's not a job so simple as you think...

The current list is incomplete and has errors, for example pin #34 is listed
two times: First as /OE and then as PRTSEL.

I've identified a few of the unlisted pins:
By checking the Expert Dplus schematic (from MSXpro site) and cross referencing
it with the EXCELLENT Toshiba HX-51 reverse engineered schematic done by AndyPF
(Great Job!), I've been able to determine these pins functions:

Pin #16 Name= NTSC Function= selects between NTSC/PAL video output.

Notes: The Gradiente is a NTSC machine and has this pin wired to VCC.
The HX-51 Is a PAL machine and has this pin wired to GND via Jumper JP3.

Pin #133 Name=/M1 Function= /M1 Negated clock signal

Pin #131 Name=/PBSY Function= Printer Busy

Pin #132 Name=/RFSH Function= Refresh signal

Note: The wiki pinout assigns both M1 and /RFRS to pin 132.

Then there are these other few, that unfortunately depend on how the computer is
internally wired, so they have different names in the two machines.

Pin #15 Name = /OE (on Expert) /RE (on Toshiba) Function= Read enable?
This pin is used in two different ways: On the Expert is connected to the
RAM, while on the Toshiba is connected to the VRAM.

Pin #106 Name = Caps (on Expert) /KBD2 (On Toshiba) Function= Keyboard related

Pin #114 Name = KS4 (on Expert) Y4 (on Toshiba) Function=Keyboard related

Par Manuel

Ascended (19691)

06-03-2023, 23:19

The keyboard of the Nikko has the double-quote above the 2 and a Yen key. Which MSX keyboard layouts have that?

Also, the text at the back near the connectors is in Japanese... what does it tell you?

Par gdx

Enlighted (6449)

07-03-2023, 01:13

Pentarou wrote:

Both of you wrote those info without having any concrete proof, moreover Mars2000 did show you that there are PAL and NTSC machines with both T7927 & T7927A.

You're lying.

Pentarou wrote:

I may be wrong, because I can't really see well in the photo...
But if I'm right and someone connects a PSU wired according to the wiki description, then what happens to the machine?

That's why it's written: probably. It's not certain. I also asked for confirmation in the Nikko computer thread.

Par gdx

Enlighted (6449)

07-03-2023, 08:28

mars2000you wrote:

Pinouts are not my speciality, but I think the pins should be ordered in numerical order, so it would be easier to read the table and optionally detect the missing pins in the wiki.

I grouped the different features with a separator between each. Maybe it's better that way.

Par mars2000you

Enlighted (6575)

07-03-2023, 09:34

gdx wrote:

I grouped the different features with a separator between each. Maybe it's better that way.

The separator is indeed a good idea. In this case, the numerical order would split the elements related to a feature.

In some way the same problematic as using the feature approach or the alphabetic appoach for the MSX-BASIC instructions, but as we are here on a very technical leved, the numerical order would be double waste of time (creation and using) while it's not the case on programming level for the alphabetic order.

Par Pentarou

Hero (568)

07-03-2023, 20:26

gdx wrote:

You're lying.

It's written in the thread, so the liar is you

Pentarou wrote:

That's why it's written: probably.

You cheated by adding "Needs confirmation for polarity" later, but fair enough.

In the Nikko Wiki page, regarding the line "Needs to see if the T7937A pin 16 is connected to VCC":
If you look at the chipset photo, you can see that pin 16 and 19 (VCC) are linked.

Don't know who did the cleanup of the T7937A page, probably Acet Now it's much better.
However I think some of the remaining pins can be assigned to these functions:

pin 82 JIS/50 Keyboard arrangement control (Verified in the Expert schematic)
Pin 83 Kana led control (Expert schematic)
Pin 106 Caps led control (Verified in both schematics)

Pins 110~118 are used in the Keyboard matrix on the HX-51 (Y0~Y8)

Par Manuel

Ascended (19691)

07-03-2023, 22:36

Guys, please do not call each other liars... that definitely doesn't help to understand each other.