Paradroid STE DMA issue blog

[Steve]

Roger Dodger me old codger

Time for more testing!

PXL_20210204_113358335.jpg

[exxos]

Roger Dodger me old codger
Time for more testing!

:fire: :fire: :fire: :fire: :hide:

[Steve]

Okay problem still persists... But guess what just arrived in the post:

PXL_20210204_130348018.jpg

A couple of ASCI2STM's made by masteries :) it will be useful to try another ASCI solution to see if any results change.

[Steve]

No jazz...

Infact a little worse as it corrupted in both 32mhz and 8mhz modes. But still an interesting result, showing that the ASCI device can influence the result.

PXL_20210204_133052831.jpg

Just thinking out loud. As @exxos said it makes no sense for the Ultrasatan to be working in 32mhz but not 8mhz since the booster operates in 8mhz mode during DMA transfers. But since a read/write request has to be initiated by the ASCI device, R/W has to be high to initiate write and low to read. I wonder if the properties of RW change slightly depending on whether the machine is running in 8/32mhz. I don't have a probe currently so perhaps @geogeo_28 could check since we have the same issue?

[exxos]

Can you scope RW and A1 on the DMA chip ?

[Steve]

And just for anyones information - masteries STe also doesn't work on write either...

https://www.atari-forum.com/viewtopic.php?f=15&t=40000

I am begging to think anyone with an STe should just avoid ASCI.

I don't have a scope right now, I'm hoping geogeo can have a look so I pinged him.

[exxos]

I am begging to think anyone with an STe should just avoid ASCI.

Try it on a H4 or H5, if it fails on there, then we in trouble :lol:

[Steve]

@exxos okay good idea I'll do that. By the way if I wanted to improve grounding on the CPU and/or DMA chip, what would be the best method? Removing the GND pin and soldering the pin directly to GND of the 4700uf cap? Stuff like this actually helped with my Falcon in the past... just wondering.

[stephen_usher]

That sort of problem happens on the STFM too, not just the STe.

[exxos]

By the way if I wanted to improve grounding on the CPU and/or DMA chip, what would be the best method?

You can't.. you have to replace the motherboard and do the grounding properly..

The only possible way would be to solder every ground point to a sheet of copper.. but nobody is going to go to those lengths..