exxos's Atari, Amiga & retro forum

Loosing quite a bit on sequential write performance?

alexh wrote: 15 Apr 2026 16:42 Loosing quite a bit on sequential write performance?

Not sure I follow.. Seq writes has the 2nd place best performance..

D'oh I didn't read the legend properly and had the two mixed up. Nice increases then.

Been walking past a box of these for the past few months and decided it was time to actually unpack them !
Rev 5.66 we on now ! This on has way more series termination resistors to solve (hopefully) all the GND bounces issues all over the place!

These use SH1000H TG155 with Surface Finish ENIG (gold) . I went with gold as a lot of other batches the PLD pads were just terrible and not even at all. They was a huge problem to solder!


Looks like the price of DRAM is now £10 a pop! :roll:

That's a good point re the pld pads.

The usual suspects are here if you need a few more guinea pigs :lol:

PhilC wrote: 27 Sep 2026 21:18 That's a good point re the pld pads.

Yeah, said before, maybe even took images of how bad some of them was. No way it be possible to solder a PLD directly onto the PCB as they was.

The usual suspects are here if you need a few more guinea pigs :lol:

:D Yeah might really even be next year before I even have time to build one up. Just way to many projects on the go at the moment.

Only got 5 PCBs built this time. The cost of the upgraded PCB material + PLD + PCB as shown now comes as just shy of £200 a pop now. Either prices have gone up massively (probably so looking at the RAM) or I priced them up wrong before. Maybe both.. I dread to think what a next batch of the DFB1X would even cost now :(

I would previously have said send them to me and I'd do them for you.

Tourettes and neuropathy make my shakey hands even worse, so you might be safer doing it yourself :lol:

PhilC wrote: 27 Sep 2026 21:40 you might be safer doing it yourself :lol:

:lol: yeah its perfectly understandable. I'm mostly trying to catch up on everything else first which has been outstanding as the whole ST536 project has dragged on for a enormous amount of time already. Once I pick it up again that will probably be another six-month round of testing I will have to do...

What concerns me more than anything, is the whole cost of the project so far has been enormous. Prices on stuff are not getting any cheaper which isn't helping either. Problem being when I find a bunch of false and do edits to the boards to fix them, and intends to reveal other faults.. It just becomes a point where you just have to re-spin the board and hope there are no more weird issues anywhere. But not really holding my breath on that one.

The last big one was ground bounce all over the place on the board and in between the motherboard and 536 itself. I'm hoping that will be what was causing the reset line glitches and a bunch of other things. Of course fighting the boards failing has added another layer of complexity to it all as well.

I really do wonder how long that has been a problem and I've been thinking its firmware issues, which there have definitely been a lot of firmware issues, but I don't think that's the full story. I've been perpetually locked in the board acting weird, fixing the firmware, and any words for a few days and then goes nuts again.. And yet, when you guys are testing the boards, the firmware fixes I did, make things worse for you guys.. And these are basically identical boards..

So I suspect I've been trying to tune firmware to a basically failing board a lot of the time. I managed to work though it enough for it to work, I think it solved, go back 2 days later and it's like the fault has moved again.. Rinse and repeat.. So I think multiple failing vias have plagued the whole project right from the start. Mix in ground bounce issues and it's no wonder the whole thing has been a nightmare.

I really do hope the more expensive PCB material will save me a whole world of pain this time around.. All the timings I already went through in the firmware and measured it all on my scope. So not messing with the firmware again ! There's been that many hardware changes on the ST536 itself, I'm not making any more changes on those boards. The last batch should solve ground bounce issues between the two boards..

There should theoretically be nothing left to go wrong.. But that's the problem, major issues can mask several smaller ones. And it's not until you get rid of the main ones that the small one start to appear.. This is no way to tell without working through them all basically one at a time.. And after several edits you just end up having to re-spin the board :roll: