Atari STe 1040 trashing UltraSatan SD card

[exxos]

The problem was that whenever the UltraSATAN was plugged in and switched on the floppy couldn't read or write anything. This had been getting worse the more I'd used the UltraSATAN.

What machine was this ?

[DoG]

When I fixed the USB on one of mine US I opened up the other one as well and took photo of them side by side. Seems that 220R, diode, and 100R is still used for level shifting on data lines where the ASCI port is. Both of these are from Lotharek.

UltraSatan v1.2 bottom.jpg

[exxos]

When I fixed the USB on one of mine US I opened up the other one as well and took photo of them side by side. Seems that 220R, diode, and 100R is still used for level shifting on data lines where the ASCI port is. Both of these are from Lotharek.

:thanksyellow:

I will try and open up mine later but I suspect it is the same as yours.

Pretty bad way of level shifting when you could just use a MOSFET anyway :roll:

[ijor]

Sorry, the following reply got lost when I edited my post ...

I think the pull-ups are mostly to reduce ground bounce and noise inside the DMA chip when the bus is idle, that otherwise would be floating.

It's not just idle though. The pullups fix HDD and floppy drive issues. The bus has to be active in that case.

But the bus always has idle period, even when you read or write sectors, the bus is still idle for a significant amount of time; probably too much for the bus to be floating. Certainly for floppy operation, where you have periods of ~30us between bytes with the bus idle. But even for ACSI, the bus is still idle at the start or at the end of the operation.

Consider what happens when you write a sector to an ACSI hard disk. The first DMA transaction happens with the ACSI bus idle and floating (if there are no pull-ups). Furthermore, it could have been idle (and floating) for a very long period before the transaction. Note that the DMA chip doesn't start driving the ACSI bus until one whole DMA buffer is filled.

The problem was that whenever the UltraSATAN was plugged in and switched on the floppy couldn't read or write anything. This had been getting worse the more I'd used the UltraSATAN.
I had to replace the DMA chip to get things to work again.

Floppy didn't work but the US and ACSI still worked fine?

[exxos]

Still the same then :(

IMG_0590.JPG

IMG_0591.JPG

IMG_0592.JPG

[zChris]

Opps!

In order to try and fix the DMA issue with US on this machine i started doing the DMA pullups fix.
But i accidently put 2.2k ohm on P100 which should be 1.2kohm... So i was wondering how bad that is? Will it work anyway or is it crucual with 1.2k ohm there?

[exxos]

In order to try and fix the DMA issue with US on this machine i started doing the DMA pullups fix.
But i accidently put 2.2k ohm on P100 which should be 1.2kohm... So i was wondering how bad that is? Will it work anyway or is it crucial with 1.2k ohm there?

It may work for testing but how stable, who knows as I doubt anyone has put it to the test. Atari themselves did that fix. So should be done.

[zChris]

Alright. Got any good ways to test if the DMA pullups are working ? Like creating folders or something ? I have saved the preferences in Devpac and the TOS desktop and that work alright, which didnt work before.

[exxos]

Alright. Got any good ways to test if the DMA pullups are working ? Like creating folders or something ? I have saved the preferences in Devpac and the TOS desktop and that work alright, which didnt work before.

See here :

https://www.exxosforum.co.uk/forum/viewt ... ?f=25&t=43

[zChris]

Darn it still gets trashed. Maybe its important that its 1.2k ohm. What else can one do if that still doesn't help with the trashing ?