Search found 491 matches

by Arne
Mon Feb 25, 2019 8:41 am
Forum: Hardware
Topic: Atari 520 STE memory problem
Replies: 34
Views: 2773

Re: Atrai 520 ste memory problem

spiny wrote:Has the onboard RAM been disabled ?

LOL :mrgreen: YMMD

Have you read the headline?
by Arne
Sat Feb 16, 2019 8:43 am
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

So I got it running to some point. With test-kit it performs: R - RAM: OK D - DMA: OK T - Timing: OK S - Serial: OK M - MIDI: OK F - Floppy: Quick Test: OK F - Floppy: Extensive test: fail F6 Read compare error 0200 4200 Track 00 Sector 10 F6 Read compare error 0300 4300 Track 00 Sector 10 F6 Read c...
by Arne
Sat Feb 09, 2019 8:03 am
Forum: Hardware
Topic: I just bought an Atari Mega ST4 with hard drive in it!
Replies: 28
Views: 2438

Re: I just bought an Atari Mega ST4 with hard drive in it!

rcamp48 wrote:Question:If I remove the Viking card will I looses Ram ? Or is the ram on that card used for video?

Of course it's used as screen memory. If you need drivers you can get them from my downloads section.
by Arne
Thu Feb 07, 2019 7:40 pm
Forum: Hardware
Topic: Need help to reproduce the Mega Mix 4 hardware
Replies: 3
Views: 493

Re: Need help to reproduce the Mega Mix 4 hardware

This interface is used to connect up to four MegaST/STE or TT keyboards to a MegaST/STE/ or TT?
How are the inputs mapped onto the output? Via mechanical switch?
If so then you may think about using multiplexers like 74HCT157.
by Arne
Thu Feb 07, 2019 10:24 am
Forum: Hardware
Topic: Atari ST MMU
Replies: 4
Views: 706

Re: Atari ST MMU

TeX38 wrote:When there is a problem with an ST, does the CAS signal get stopped or have I got a faulty MMU? (C025912)

No /CAS on upper or lower bank? Just verified it and I see that there is /RAS activity at boot time on the upper bank but no /CAS activity. On lower bank /RAS and /CAS are active.
by Arne
Mon Feb 04, 2019 5:28 pm
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

by Arne
Mon Feb 04, 2019 5:03 pm
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

Did a little sketch. https://i.ibb.co/Ph7QLkX/TagRAM.gif Cacheable area: 4MB Cache size: 64KB Given that the DataSRAM (not on sketch) is 64KByte in size A[15..2] are connected to the address pins of the SRAM used for storing the Tag. So A[21..16] form up the Tag that needs to be stored/read. So thes...
by Arne
Mon Feb 04, 2019 4:21 pm
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

Heh :) Saves me typing out an explanation of how it works using just static RAM (at the expenses of a few wait states) Steve I'd read it with delight. Always eager to learn something new :D If someone with this accelerator looks for drivers: I have put a ZIP into the Downloads section of my homepage.
by Arne
Mon Feb 04, 2019 3:02 pm
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

Case closed. I should have checked more thoroughly :oops:
Beneath three of the four ROM sockets are three MK41H80 Tag RAMs.
by Arne
Mon Feb 04, 2019 2:43 pm
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

Some side notes. I thought that the Hypercache 030 boots into KAOS but seems to contain a patched 1.04 The bootscreen is pretty interesting as it contains the address of the Bavarian Broadcasting in Munich! https://i.ibb.co/dWxCJpP/IMG-0719.jpg Desktop info gives this: https://i.ibb.co/z7dmFpx/IMG-0...
by Arne
Mon Feb 04, 2019 1:10 pm
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

Thanks for the explanation on Tag. But I know that already! I dug into the Mach16 schematic and IDT datasheet some years ago. Besides I've studied Computer science. Anyway: I looked into the topic of creating a TagRAM with standard Static RAM and external logic two years ago. Problem is that IMO man...
by Arne
Mon Feb 04, 2019 10:00 am
Forum: Hardware
Topic: Pro VME Hypercache 030
Replies: 14
Views: 1616

Re: Pro VME Hypercache 030

I found the accelerator card in one of my drawers these days. Anybody able to answer my questions? There are 10 74HCT573 latches between the 68000 and the FPU socket and 8 MCM6168P55 (4K x 4 55ns SRAMs to my knowledge) between TOS EPROMs and CPU/FPU. The ICs with stickers are 16V8/22V10.
by Arne
Sun Feb 03, 2019 8:02 pm
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

So I am narrowing down the source of the CLK8 problem - at least I think so. I have reworked the CLK8 generated by MMU so that I totally ignore its CLK8 and use CLK16 to feed at frequency divider (74F74) and use its output as the new CLK8. Gives me a nice clock with 4V at its highest and only 200mV ...
by Arne
Fri Feb 01, 2019 6:37 pm
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

As I said the CLK8 generated by MMU didn't look like what I expected. This is it: https://i.ibb.co/vBfznL3/ClockOrg.gif I had the feeling that I should rework the CLK8 so I put a 74F32 on top of the 74LS11 next to MMU and wired it like this: https://i.ibb.co/xgwWsqZ/Schematic.gif R113 is the origina...
by Arne
Fri Feb 01, 2019 9:53 am
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

Back in business - repaired the CLK8. It still won't go down to 0V. Lowest peak I see on the scope is around 600mV. Usually clocks on the Ataris I saw so far undershoot GND by >1V. Will check it on a 1040 later. I see the /HALT signal come and go. /RESET is high. When pushing the Reset button both g...
by Arne
Wed Jan 30, 2019 9:39 pm
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

Everytime I touch the board it's getting worse.
Now I don't have a CLK8 anymore - it's constantly high. CLK4 is constantly low. CLK16 into MMU OTOH is fine. I put the MMU into a 1040 and the system boots properly...
by Arne
Wed Jan 30, 2019 9:06 pm
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

CLK8 looks fine just doesn't reach 0V

Image

GND/Vcc on CPU is at 4.9V
by Arne
Wed Jan 30, 2019 8:41 pm
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Re: Dead MegaST

Thanks for the suggestions. I moved the board to inspect the bottom side and since I pressed the PSG into its socket I cannot recreate the scenario again :-/ The system behaves now without any signal change on any signal at all, except /HALT and /RESET when pressing the Reset button. /BERR is consta...
by Arne
Wed Jan 30, 2019 4:24 pm
Forum: Hardware
Topic: Dead MegaST
Replies: 11
Views: 1313

Dead MegaST

Hi Folks, I got this MST with strange behavior. It won't boot at all and cycles through the same "signal loop" i.e. every 8µs (= 64 CLK8) it shows the same picture on the scope: https://i.ibb.co/3yFhNfG/DS1104-Z-20190130-171134.gif I checked other signals (with the pink colored probe) whic...
by Arne
Tue Jan 15, 2019 2:55 pm
Forum: Coding
Topic: MetaDOS DOS-Driver
Replies: 1
Views: 608

MetaDOS DOS-Driver

Hi all,

is there any source of information how to write a DOS driver for MetaDOS. I just found the MetaDOS Developer Documentation Jan.3rd,1989 which is about the BOS driver.
by Arne
Mon Jan 14, 2019 10:17 am
Forum: Hardware
Topic: STfm without video signal through the DIN port.
Replies: 14
Views: 1284

Re: STfm without video signal through the DIN port.

Atarieterno wrote:(...) not send a video signal (...)

What exactly do you mean with video signal? Composite video, RGB or Mono video?
by Arne
Mon Jan 14, 2019 9:25 am
Forum: Hardware
Topic: STfm without video signal through the DIN port.
Replies: 14
Views: 1284

Re: STfm without video signal through the DIN port.

⋅  do you own an oscilloscope? ⋅  did you connect an SM124 (or compatible) or SC1224 (or compatible) to the DIN plug? I have a 1040STFM board currently on my workbench so I could send you specific screenshots of my oscilloscope on certain test points. Get the schematic and check...
by Arne
Mon Jan 14, 2019 8:17 am
Forum: Professionals
Topic: Dead Falcon - no boot / coloured screen only
Replies: 38
Views: 3701

Re: Dead Falcon - no boot / coloured screen only

As usual in case of a dead unit:
  • download the service manual
  • read chapter Troubleshooting a dead unit ch.3.3 in my copy
  • act accordingly
As RAM seems to be completely down a test cart is probably of no use here.
by Arne
Sat Dec 22, 2018 5:41 pm
Forum: Professionals
Topic: TT Clock Battery
Replies: 33
Views: 6101

Re: TT Clock Battery

What TT mainboard? PGA+daughterboard, PGA w/o daughterboard or SMD CPU?
by Arne
Sat Dec 22, 2018 3:28 pm
Forum: Professionals
Topic: TT Clock Battery
Replies: 33
Views: 6101

Re: TT Clock Battery

dhedberg wrote:I replaced the battery but I have the same problem. A lot of times between power-ons it loses the time. Haven't had the time to look into it. Battery is fine.

Some TTs need 6V batteries, some 3.6V IIRC.

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