HB-F9S v9938 partially dead?

Pagina 6/6
1 | 2 | 3 | 4 | 5 |

Van flyguille

Prophet (3028)

afbeelding van flyguille

03-01-2016, 17:20

This thread let thinking that we can gain 20% speed up, just unhooking the M1 /WAIT mechanism, but for maintain compatibility with msx2 software (no demo scene) we can hook the v9958 /wait line instead.

Ofcouse it will be only for msx2+ upgrades (with or without new ROM set).

That is just some wiring for those who already has the v9958 set, no extra components needed.

Van flyguille

Prophet (3028)

afbeelding van flyguille

03-01-2016, 17:39

We already know that the lack of buffering in the MSX MB didn't prevent it fail.

But the same thing we can say from the IDE cartridge, that did a direct connection of the /WAIT direct to the IDE bus.

So, no prevent here, no prevent there, and ofcourse the CF card itself is not made to meets the AC signaling MSX standard.

So, We wonders, wich exact cartridge version it is.

Can you take pictures of its PCB both sides and post the pics here (high resolution please)?.

Van sd_snatcher

Prophet (3472)

afbeelding van sd_snatcher

03-01-2016, 17:49

Quote:

This thread let thinking that we can gain 20% speed up, just unhooking the M1 /WAIT mechanism, but for maintain compatibility with msx2 software (no demo scene) we can hook the v9958 /wait line instead.

Yes, that's a quick poor's man turbo. Smile

Quote:

So, no prevent here, no prevent there, and ofcourse the CF card itself is not made to meets the AC signaling MSX standard.

It seems that the culprit was the CF card. It didn't follow the IDE standard specification for the IORDY pin. When standards aren't followed, things will break somewhere someday.

Van flyguille

Prophet (3028)

afbeelding van flyguille

03-01-2016, 18:38

sd_snatcher wrote:
Quote:

This thread let thinking that we can gain 20% speed up, just unhooking the M1 /WAIT mechanism, but for maintain compatibility with msx2 software (no demo scene) we can hook the v9958 /wait line instead.

Yes, that's a quick poor's man turbo. Smile

Quote:

So, no prevent here, no prevent there, and ofcourse the CF card itself is not made to meets the AC signaling MSX standard.

It seems that the culprit was the CF card. It didn't follow the IDE standard specification for the IORDY pin. When standards aren't followed, things will break somewhere someday.

It is an AC signaling problem, not logic/digital problem. When circuits are made cheap, no circuit has a buffer in any stage, that is what it gain, compatibility problems, (aka "AC signaling" problem, line heavy biased, or how you want to name it), I am sure the CF card meets the IDE standard by itself, but it is all the "combo" what does it fail.

Change the MSX machine, it will works.

Change the IDE cart, it will works.

Maybe MAYBE change the CF card, it will works, just on luck.

Van blackmsx

Expert (77)

afbeelding van blackmsx

03-01-2016, 18:51

flyguille wrote:

This thread let thinking that we can gain 20% speed up, just unhooking the M1 /WAIT mechanism, but for maintain compatibility with msx2 software (no demo scene) we can hook the v9958 /wait line instead.
Ofcouse it will be only for msx2+ upgrades (with or without new ROM set).
That is just some wiring for those who already has the v9958 set, no extra components needed.

Funny, I was planning to upgrade the v9938 on my machine. Im actually waiting for a v9958 to arrive from china.

flyguille wrote:

Can you take pictures of its PCB both sides and post the pics here (high resolution please)?.

The board is exactly like this one: http://www.msxpro.com/msx-ide.html
I'll see if I can take some pictures and post them here.

sd_snatcher wrote:

It seems that the culprit was the CF card. It didn't follow the IDE standard specification for the IORDY pin. When standards aren't followed, things will break somewhere someday.

It certainly seems so, but its strange that all 3 CF cards I tryed (different brands) caused the same problem.

So far the interface has been working just fine without the /WAIT signal.

Van flyguille

Prophet (3028)

afbeelding van flyguille

03-01-2016, 19:18

blackmsx wrote:

It certainly seems so, but its strange that all 3 CF cards I tryed (different brands) caused the same problem.

So far the interface has been working just fine without the /WAIT signal.

that answer the previous post to that one. It is a design fail, a design that was looking for cheapness you can be sure of that!.

The first vendor that is culprit is SONY for making the HB so cheap that didn't spend in a single TTL chip, as others MSX based on s1985 has.

Then the ide cart maker didn't visualize that maybe MAYBE is a risk to not buffer MSX bus lines and connect it directly to IDE bus, hoping it is the same AC/CC signaling standard (CC because it is a BIAS problem, when a line is heavyer biasses to +5V is called CC problem, that offsets the AC signal out of the TTL threshold). So , no buffer in the cart, no prevent the problem from happening. That cartridge will work perfectly on others more expensive msxs, but not on that one that don't has buffering.

Pagina 6/6
1 | 2 | 3 | 4 | 5 |