MSX FLEX project

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Van bore

Expert (115)

afbeelding van bore

10-05-2019, 09:06

If the cart causes the self-clocking you won't really see any difference on the different edges of the cable, and pull-up/pull-downs won't help either.
What you would be looking for in that case is if there is a small ripple when then clock transitions from high to low or low to high that could make the cart think it is two clock cycles.

If that is the case a schmitt trigger on the clock signal would help.

Van Alexey

Guardian (2177)

afbeelding van Alexey

10-05-2019, 20:17

With the help of a few guys including our group's engineer the solution has been found. The 100 Ohm resistors installed for the data bus solved the instability problem for all cartridges except one (IDE-FDD controller). So I will modify the original design to include those resistors by default.

There were a few attempts to make the IDE-FDD controller to work by installing resistors for the signals that it gets from the slot. It booted only after BUSDIR and RD lines got the resistors installed for them. But the installation of the resistors for other signals that it used (IORQ, SLTSEL, WR) didn't help or even made things worse. So I decided to abandon this solution and only use 8 resistors for the data bus. This cartridge is not widely used and Carnivore2 is its successor.

I will assemble a few devices and contact those who wanted to buy them.

Van Alexey

Guardian (2177)

afbeelding van Alexey

17-05-2019, 01:51

Final version:

Van rderooy

Hero (537)

afbeelding van rderooy

17-05-2019, 14:21

Nice job Alexey. Will this version connect to the Expansion slots as-is (apart from the dual keys issue on some) or do you need to add a second connector or remove the key also for single-key Expansion slot systems?

Van Alexey

Guardian (2177)

afbeelding van Alexey

17-05-2019, 15:06

Ok, here's the problem. I have only SVI-728 to test and unfortunately the key on the FLEX cable connector is incompatible with its expansion slot connector. I had to remove the key in order to connect the cable to 728 (see the image earlier in this thread). However I noticed that the connector of the SVI-728 is different than the expansion bus shown in this article (it's flipped - pin 1 is on bottom-left):

https://www.msx.org/wiki/Expansion_bus_slots

If the expansion bus connector would be like shown on the picture in this article, then the key on the FLEX cable could be compatible with the single keyed expansion bus connector of the MSX. But as I said, I have no suitable computers to verify that compatibility.

So if you are going to connect FLEX to the standard expansion bus, you need to make sure that the cable is connected the right way. It's easy to verify because FLEX has both GND pins as well as both +5V pins connected on the boards. So you will need to measure the continuity between 2 pins to identify where GND and +5V are on the FLEX's connector. And you need to do the same on the pins of the expansion bus that the cable is going to be connected to. If those pairs of shorted pins match, then the cable can be safely connected to the expansion bus.

Van -Neo-

Champion (375)

afbeelding van -Neo-

18-05-2019, 09:05

@Alexey I'd like to acquire one (for 50pin-50pin use). How can I (pre) order?

Van Alexey

Guardian (2177)

afbeelding van Alexey

18-05-2019, 11:06

I am not selling yet. Only a few ready sets will be sold. The set includes both 50 and 60 pin modules and the cartridge module. The price will be around 60-70 Euro for the complete set. I am currently experimenting with black plastic and laser engraving of the logo and letters.

Van sdsnatcher73

Champion (404)

afbeelding van sdsnatcher73

18-05-2019, 14:51

Oh cool! I’d prefer black plastic actually, then again I’d take it if no matter what the color Wink

Van Alexey

Guardian (2177)

afbeelding van Alexey

18-05-2019, 23:42

The logo was successfully engraved with the laser engraver. So the letters could be done the same way as well. I think the black version will be somewhat exclusive...

Van Alexey

Guardian (2177)

afbeelding van Alexey

10-06-2019, 01:18

When printed in black, the cases need engraving. So far it looks like this:

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