exxos's Atari, Amiga & retro forum

Forgottenmyname wrote: 03 Mar 2019 12:33 I don't mind having a go exxos, as long as you don't need the results in a hurry (work is busy at the moment and the wife has me decorating )

Been 5 months so doubt much longer make much odds :)

I may have a couple more somewhere if anyone else wants to build one.

Very True, promise it won't be another 5 months :-)

Got the MMU adaptor built just now, except for the two caps on the bottom, which I don't have values for.

Do you remember what values C1 and 2 are exxos?

Photo of assembled adaptor

PhilC wrote: 27 Mar 2019 21:43 Do you remember what values C1 and 2 are exxos?

Ah sorry, didn't think about it.. There are just such as 100nF.. you don't need them for testing...

PhilC wrote: 27 Mar 2019 21:45 Photo of assembled adaptor

:bravo:

exxos wrote: 27 Mar 2019 21:53

PhilC wrote: 27 Mar 2019 21:43 Do you remember what values C1 and 2 are exxos?

Ah sorry, didn't think about it.. There are just such as 100nF.. you don't need them for testing...

PhilC wrote: 27 Mar 2019 21:45 Photo of assembled adaptor

:bravo:

I'll put them on tomorrow and try it in my Mega, just checking, does the words MMU line up with pin 10?

PhilC wrote: 27 Mar 2019 21:58 I'll put them on tomorrow and try it in my Mega, just checking, does the words MMU line up with pin 10?

Fingers crossed for success. Looking good PhilC / Exxos.

PhilC wrote: 27 Mar 2019 21:58 I'll put them on tomorrow and try it in my Mega, just checking, does the words MMU line up with pin 10?

Yep, think its the small cut out on the corner of the chip.. I need to label that up better...

EDIT: oh I see now pin 1 is actually marked on the silk screen, just not very easy to see as its on the edge of the PCB.

2 x 0805 100nf caps added to the bottom of the board.
Test candidate is a Mega 1 that's been upgraded to 4mb using SOJ20 adaptors and smt ram, with the extra wired wired to the top of the MMU socket.

I had to temporarily remove the extra wire, putting the machine back to 1mb mode. Really must stop being lazy and connect this properly on the bottom of the pcb.

The good news is the board boots first time with tos 1.04 but only shows 512k. Checked again by booting with z diag cart and it still only shows 520k. Putting the normal MMU in returns the ram back to 1mb. So I guess I've either got a dry joint on a track or I need to fit an unf*ck wire somewhere.

Definitely going in the right direction though, so well done exxos :dualthumbup:

Nice :)

Maybe check MAD8...

Its possible something may be wrong, as the pinouts for the chips is a little questionable at best..