NetUSBee Lite problems on TT: Any thoughts?

Problems with your machine in general.
User avatar
stephen_usher
Posts: 5578
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by stephen_usher »

OK, after more testing I think that I can say that the problem is that the writes to the device aren't happening.

For those not in the know, the trick being used to write is to put the data into one byte of the address whilst doing a read cycle. From what I understand the device then picks up the value held in the address and writes it into a location held elsewhere in the address. For whatever reason this is not working.

Can the hardware people think of possible reasons for this on some TTs but not others? Voltage loss on the address bus making it too low for the NetUSBee device to read reliably? If so then why can it access the device ROM and do reads?

I'm flummoxed.

(I've cleaned the ROM port as best I can. I've pushed the tines in so they make harder contact. I've looked at them under a magnifying glass and they all look OK.)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
User avatar
stephen_usher
Posts: 5578
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by stephen_usher »

Looking at this a bit further: If I run ht1ene.tos test continuously it will eventually crash with "Illegal Instruction". It will do this at a random time, sometimes quite quickly, which suggests that maybe there's a poor interaction between the data bus and the RTL ethernet chip causing corrupted instruction fetch by the CPU. More evidence pointing to this is that if the CPU cache is turned off it happens more quickly.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
User avatar
exxos
Site Admin
Site Admin
Posts: 23494
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by exxos »

I don't know about either thing.. But could it be a bus loading issue as I've had that problem on my ste recently..where plugging in a cart would give the impression of bad tos ROM.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
czietz
Posts: 548
Joined: Sun Jan 14, 2018 1:02 pm

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by czietz »

As far as I know, the NetUSBee design is available to the public. So maybe someone should review the schematic. Could be (capacitive) loading of the bus, but could also be that the buffers on the NetUSBee due to some glitch in the logic design output data to the bus when they shouldn't do so.
User avatar
stephen_usher
Posts: 5578
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by stephen_usher »

I've downloaded the documentation but it doesn't seem to have a logical diagram, merely a set of board layouts for a certain PCB design program.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
czietz
Posts: 548
Joined: Sun Jan 14, 2018 1:02 pm

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by czietz »

In the download I do see the schematic file: version1.sch.
However, as you mentioned, it is for the less well known design software Number One Systems EasyPC. Now, I don't have a NetUSBee and won't get invested in this. But you could try if the schematic can be opened with the demo/trial version of said program: https://www.numberone.com/. Or you could redraw the schematic from the PCB layout (provided in industry standard Gerber format) or from your actual hardware.
User avatar
stephen_usher
Posts: 5578
Joined: Mon Nov 13, 2017 7:19 pm
Location: Oxford, UK.
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by stephen_usher »

The software method is probably the only way given that the Lotharek board is multi-layer and has an upper paint layer obscuring all the tracks.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
User avatar
rpineau
Posts: 534
Joined: Thu Aug 17, 2017 6:08 pm
Location: USA
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by rpineau »

The schematics seems really simple and is available in the etherne.zip file in the ETHERNEC directory as SCHEMAT.GIF :
SCHEMAT.GIF
SCHEMAT.GIF (9.07 KiB) Viewed 5072 times
This doesn't have the USB part but the ethernet part is there.
Working ones : MegaSTE (68020) / TT030 / Falcon with AB040 & Eclipse / 1040STF
Need testing : Falcon with CT2
User avatar
rpineau
Posts: 534
Joined: Thu Aug 17, 2017 6:08 pm
Location: USA
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by rpineau »

I downloaded the demo version of the Easy PCB software (you have to register with them... little bit annoying) and I can open the sch file for the NetUSBee.
So we should be able to redo it in Eagle.
Working ones : MegaSTE (68020) / TT030 / Falcon with AB040 & Eclipse / 1040STF
Need testing : Falcon with CT2
User avatar
rpineau
Posts: 534
Joined: Thu Aug 17, 2017 6:08 pm
Location: USA
Contact:

Re: NetUSBee Lite problems on TT: Any thoughts?

Post by rpineau »

The access for the RTL8019AS is exactly the same as the original ethernec :
Screen Shot 2018-04-29 at 15.57.40.png
Screen Shot 2018-04-29 at 15.57.40.png (195.6 KiB) Viewed 5062 times
Working ones : MegaSTE (68020) / TT030 / Falcon with AB040 & Eclipse / 1040STF
Need testing : Falcon with CT2
Post Reply

Return to “HARDWARE ISSUES”