Slot Expander | MSX Resource Center

Hero (644)

11-10-2018, 15:55

Well, it clearly has a subslot register and decoder chips, sot it definitely should work with ROMs.

Otherwise, I'm no expert and have little experience with slot expanders. Perhaps (I'm just guessing here) ROM cartridges you tried were those kind that need to be booted up (ROM games, HDD/floppy interface etc.)? It might be that carts can only boot from a primary slot. If you need something more advanced, you need to have an OS or some software which will look for the ROMs and use them accordingly. I could be way off here, though!

Did you try to run slotmap.bas or something similar?

EDIT: I meant slot.bas, or msxmem2, or this utility: http://www.tiny-yarou.com/slotchecker.html . Also see this thread

EDIT2: Or: https://www.msx.org/forum/msx-talk/software/msxmem2

Por Wolverine_nl

Paragon (1159)

11-10-2018, 15:57

Most cartridges like Megaflashrom SCC+SD, GR8NET, Carnivore2 etc. can only work from a primary slot, so one of your basic physical MSX slots. There are also some games that only work in a primary slot. So it could be a coincidence.

Por Jipe

Paragon (1552)

11-10-2018, 16:42

see this schéma
slot X4

Por blackmsx

Expert (77)

12-10-2018, 11:47

Thanks guys for all the answers.

The cartridges I tried (and did not work on subslots 2,3 and 4) were Konami Tennis, Choplifter, a Sunrise IDE compatible IF (with Nextor ROM) and a TDC600 clone...Im aware that carts that already implement expanded slots by themselves (Carnivore, MFR, etc) will only work on the main MSX slot.

I will try these utilities to see whats going on there, and of course I will check my circuit for any errors...

@Jipe, actually that schematic was my first attempt to build an expander some months ago but I could not get it to work. I might give it a try again. The 74ls352 could be replaced with a 74ls153 and then leave out the 74ls00 at the output, right?

Por Jipe

Paragon (1552)

12-10-2018, 13:46

the big post for this slot expander is here ( in french )
see the L-olivera remarq at the end

http://msxvillage.fr/forum/topic.php?id=881&pt=1

Por blackmsx

Expert (77)

12-10-2018, 14:18

blackmsx wrote:

Thanks guys for all the answers.

The cartridges I tried (and did not work on subslots 2,3 and 4) were Konami Tennis, Choplifter, a Sunrise IDE compatible IF (with Nextor ROM) and a TDC600 clone...Im aware that carts that already implement expanded slots by themselves (Carnivore, MFR, etc) will only work on the main MSX slot.

I will try these utilities to see whats going on there, and of course I will check my circuit for any errors...

@Jipe, actually that schematic was my first attempt to build an expander some months ago but I could not get it to work. I might give it a try again. The 74ls352 could be replaced with a 74ls153 and then leave out the 74ls00 at the output, right?

Thanks!

Its not clear to me which of the two designs cannot use RAM/ROM on page 4, yours or the one I posted here?

In short, is the 74xx02 needed between the main slot and the 74xx139?

I'll investigate further

Por Danjovic

Master (222)

12-10-2018, 21:17

You can do it without the lS02 as shown in second diagram at msxpro page:
http://www.msxpro.com/slotexp.html

Por blackmsx

Expert (77)

13-10-2018, 11:29

Thanks, I think I got it working finally! The problem was the schematic I was working with misses the connection between LS138 pin 6 and VCC, so the pin was floating.

Still is a bit inestable. Sometimes carts are not detected, but when detected it works perfectly. Im using a 30cm ribbon cable, is that too long?

Por alali.ahmed.t

Resident (49)

13-06-2022, 03:36

I looked at older post related to this one, but since blackmsx had it working here, I wonder if anyone made a gerber file for this internal slot expansion?