exxos's Atari, Amiga & retro forum

Mikerochip wrote: 28 Jun 2025 18:22 And, I still have no idea if we can substitute in PSRAM in place of SRAM.
(I did open a git issue, but, maybe it's best to ask here??)

Sorry I missed that on Github so it was good you mentioned it here instead.

It's not a drop in replacement in that the one you mention is a BGA chip so you'd have to design a new ram pcb, and be comfortable soldering BGA's.
Apart from that, it looks like it should basically just work from a glance at the datasheet.
But.. don't you think LCSC got the decimal point wrong in their price for that (American/German) item? They don't carry it in stock and their reference price is ~10x lower compared to places like Mouser that does have it.

agranlund wrote: 28 Jun 2025 23:01

Mikerochip wrote: 28 Jun 2025 18:22 And, I still have no idea if we can substitute in PSRAM in place of SRAM.
(I did open a git issue, but, maybe it's best to ask here??)

Sorry I missed that on Github so it was good you mentioned it here instead.

It's not a drop in replacement in that the one you mention is a BGA chip so you'd have to design a new ram pcb, and be comfortable soldering BGA's.
Apart from that, it looks like it should basically just work from a glance at the datasheet.
But.. don't you think LCSC got the decimal point wrong in their price for that (American/German) item? They don't carry it in stock and their reference price is ~10x lower compared to places like Mouser that does have it.

I was just wondering if it's technically possible, is all!
[ZZ#] is tied high, so, it looked like it *should* work?

IS66WVE4M16EBLL-70BLI is readily available, but, it's 70ns. the 55ns variant definitely seemed like it might be the way to go, but, is EOL.
That's why I was wondering about the speed of them ram, really.

The 70ns variant, IS66WVE4M16EBLL-70BLI is €4 for 8MB x8bit.

I agree, that Cypress one should probably just work, or at worst be very easy to get working.
Though if Mousers price is the correct one then they are more than twice as expensive as the current ram simms :)

Those much cheaper 70ns BGA's would actually end up a little bit faster overall since they can do 70+25+25+25 sequences. Would require cpld changes to support that. Alternatively one can live with 70+70+70+70 which only requires minimal changes to add a little bit more waitstate.

agranlund wrote: 29 Jun 2025 00:42 Alternatively one can live with 70+70+70+70 which only requires minimal changes to add a little bit more waitstate.

@agranlund if you make the wait state count part of the bios setup, might be easy to change in future?
Guess we just need a new BGA PCB then :P

Small update!

Mikerochip wrote: 28 Jun 2025 18:22

terriblefire wrote: 27 Jun 2025 16:34Me too

So get building! Maybe design a way for us to hammer a tf536 or something into the Raven.
Maximum compatibility?!? :lol:

There exists boards to connect a 68060 into 68040 machines...
maybe we could go the other way?!?! design a 68040 board to run in a 68060 PGA211 socket... :mrgreen:

Or some strange side board that lets me use a 68882 with a 68LC060.... ??

Currently time is my greatest enemy

terriblefire wrote: 08 Jul 2025 16:03 Currently time is my greatest enemy

Whoever invents more of it will be rich, that's for sure :)

Small update, where I have all the smd parts that I currently have on hand, soldered up to both boards.

Waiting for a delivery, for the rest. Ho hum. (Tomorrow, by the looks of it, provided FedEx don't make a balls of it)

Well.

My soldering weeken fun ground to a halt when FedEX decided to charge me a 200% ... blackmail? (I don't know exactly what else you could refer to it as) or whatever you want to call it.
Witholding fee for my LCSC package.

So, no parts for me this weekend.

Parts came to almost exactly €140, plus FedEX delivery of €40 (I had a voucher for €20 though, so, I only paid €20).
Where they then txt me and said I owe €37 in VAT (which is fine!)
and €279 as my FedEX delivery "fee".

Jesus Christ.

I'm not exactly sure of the legality of that. But. We'll see what happens tomorrow. (Obviously, I queried it)

ouch, that has to be some kind of mistake?
Surely they can't be serious expecting a 279 eur delivery fee.

F3d3x....

I tried to ship a board overseas with them and the 'guest' quotation was about $50 or so for the size and weight. But there are certain disadvantages to shipping as a 'guest' if something goes badly so I signed up for a shipping account.

(if you try the same with DHL you need to tick boxes to agree to leave the box unsealed and permission to rummage inside!)

After weeks of trying to get them to link my 'login' to an actual shipping 'account' (??!!?? what ?) I was finally able to get a price. Still couldn't link my card though, after all that.

They wanted $300-$500 to ship the same board under the same conditions with the same dimensions and weight.

thanks but no.