Search found 588 matches

by Arne
Tue Feb 18, 2020 12:12 pm
Forum: Hardware
Topic: Atari STE only boot in High Res
Replies: 36
Views: 1314

Re: Atari STE only boot in High Res

Arne, here are the results : R215 value = 4,66 kΩ The continuity test is ok (beep!) between r215 right pin and U209 pin 12 just above. Then the monitor detection should work, especially if you can blindly handle the diag menu in colour mode (sound). So I guess the problem is more output related i.e...
by Arne
Tue Feb 18, 2020 11:07 am
Forum: Hardware
Topic: Atari STE only boot in High Res
Replies: 36
Views: 1314

Re: Atari STE only boot in High Res

Is this resolution problem frequent on the STe range? I really don't know. Switch off the STE, disconnect the power cord. The PSU can hold hazardous voltages even if switched off. So better wait 15mins until starting your measurements. On your last photo you see resistor R215. Check the resistor's ...
by Arne
Tue Feb 18, 2020 10:45 am
Forum: Hardware
Topic: Atari STE only boot in High Res
Replies: 36
Views: 1314

Re: Atari STE only boot in High Res

The HW patches are factory made. Mine has them, too.
First of all: what tools (multimeter, scope, soldering-station,...) do you have at hand and are familiar with?
Second: can you read the 1040STE schematic?
by Arne
Mon Feb 17, 2020 6:02 pm
Forum: Hardware
Topic: Wittich ISA adapter for MegaST
Replies: 20
Views: 1066

Re: Wittich ISA adapter for MegaST

Optional 68881.
by Arne
Sun Feb 16, 2020 4:51 pm
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 1069

Re: Decreasing colours (algorithm)

But finally the method I have used is to split the picture in multiple one line image files, then use XnView to convert each line file to x colors (using the batch converter and selecting one dithering method), then reassembling the converted files. So this weekend I wrote a little Delphi tool to s...
by Arne
Thu Feb 13, 2020 10:31 am
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 1069

Re: Decreasing colours (algorithm)

(...) for mixing together via interlaced frames to get you an effective palette (~100 colours?) simply with interlacing. Interesting tech but... 50Hz on a CRT is awful but interlacing frames? Wouldn't that flicker even more? Seems I am aiming for the impossible. So maybe I choose Spectrum 512 witho...
by Arne
Thu Feb 13, 2020 8:06 am
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 1069

Re: Decreasing colours (algorithm)

The idea works, but you would not really want to use RGB as you will find it doesn't really give you a good measure of similarity. If you first convert both pixels into the Lab colourspace (CIELAB / La*b*) then you will find the closeness of colours is closer to the linear distance between the poin...
by Arne
Wed Feb 12, 2020 10:05 am
Forum: Coding
Topic: Decreasing colours (algorithm)
Replies: 17
Views: 1069

Decreasing colours (algorithm)

As you all know ST-Low permits 16 colours in total to be displayed at the same time. Spectrum 512 crossed this border and can display AFAIK up to 48 colours per line. But it comes at a hefty price: 80% CPU load as I have read. So I was thinking of something else and I do not know if this is feasible...
by Arne
Mon Feb 10, 2020 7:28 am
Forum: Coding
Topic: falcon printer port ACK and select
Replies: 3
Views: 314

Re: falcon printer port ACK and select

If you would have had a look at a site explaining the parallel port - like Wikipedia https://en.wikipedia.org/wiki/Parallel_port - you would have recognised that ACK (pin 10) is an input. Furthermore: if you would have had a look into the F030 schematics you could have easily seen that SELECT (pin 1...
by Arne
Thu Feb 06, 2020 11:36 am
Forum: Hardware
Topic: Microwire Interface
Replies: 9
Views: 413

Re: Microwire Interface

joska wrote:Addressing is done via the SS

Really? :roll:
I have designed HW/SW with SPI support. I KNOW what a /CS is.
You haven't understood my post!
by Arne
Thu Feb 06, 2020 11:04 am
Forum: Hardware
Topic: Microwire Interface
Replies: 9
Views: 413

Re: Microwire Interface

@Arne where did you get that nice image? Sybex - Atari ST-STE-TT Profibuch That would be very useful indeed. E.g. you can easily connect an mp3/ogg/wav/midi decoder/player via SPI. But IMHO it could not be a generic interface for attaching an assortment of SPI slaves. Let's say you use a CPLD for p...
by Arne
Thu Feb 06, 2020 10:15 am
Forum: Hardware
Topic: Microwire Interface
Replies: 9
Views: 413

Re: Microwire Interface

If I'm not wrong, STE Microwire interface is unidirectional. Therefore there is no possible to get current status from the device behind it. Yes, that's probably what the three arrows indicate: https://i.ibb.co/Vp1rhts/Microwire-STE.gif Looks like the Microwire implementation in the STE/TT is tailo...
by Arne
Thu Feb 06, 2020 9:37 am
Forum: Hardware
Topic: Microwire Interface
Replies: 9
Views: 413

Re: Microwire Interface

Good question. Microwire is very similar to SPI. So you need a clock, MISO, MOSI and a CS signal connected to your own device. IMHO you need an address decoder (for CS) and a parallel-to-serial en-/decoder. Just google for SPI. In general I think it is easier if you design a stand-alone SPI interfac...
by Arne
Sun Feb 02, 2020 10:04 am
Forum: Hardware
Topic: Atari STE - J302 Connector short
Replies: 2
Views: 361

Re: Atari STE - J302 Connector short

Might it be that the pins of the digikey connector are a bit longer than the 4pin header and made contact with the lower part of the RF-shielding?
by Arne
Sat Feb 01, 2020 9:47 am
Forum: Hardware
Topic: Falcon floppy drive connector broken
Replies: 6
Views: 436

Re: Falcon floppy drive connector broken

vinz6751 wrote:So my question is: is it possible to disconnect the floppy drive cable that is connected to the main board ?

Yes - desolder it.

vinz6751 wrote:Is there a special technique for that ?

Yes - use an adequate solder-iron/hot air station.
by Arne
Tue Jan 28, 2020 5:06 pm
Forum: Coding
Topic: Pure C assembler help with macros
Replies: 5
Views: 619

Re: Pure C assembler help with macros

I had a look into the manual and it might work this way:

Code: Select all

FAST = 0 ; or != 0
(...)
.IF FAST
.MACRO F_MUL param1,param2
   FSGLMUL.x param1,param2
.ENDM
.ELSE
.MACRO F_MUL param1,param2
   FMUL.x param1,param2
.ENDM
.ENDIF
by Arne
Mon Jan 27, 2020 10:37 am
Forum: Professionals
Topic: Converting graphics to screen format
Replies: 11
Views: 791

Re: Converting graphics to screen format

I"m using Pixart for this task - it saves 8 bytes (IIRC) header + palette + raw bitplane data. I justed checked it with a 640x480x256 BMP (as it did not like it as PNG). File size of Pixart's own *.PIX format: 307.984 bytes. Minus unpacked data (307.200) that leaves 784 Bytes for header + pale...
by Arne
Sun Jan 26, 2020 3:23 pm
Forum: Professionals
Topic: Converting graphics to screen format
Replies: 11
Views: 791

Re: Converting graphics to screen format

With some additional coding you may use the Xnview on Windows. Save the file as "*.rawraw" (this is probably still pixel packed not Atari typical planar) but gives a 307.200byte file (for 640x480x256). With CTRL-M you can save the palette which will give you a 1024byte file (for a 256 colo...
by Arne
Mon Jan 20, 2020 7:54 am
Forum: Hardware
Topic: Atari 520ST black screen with white border
Replies: 10
Views: 1228

Re: Atari 520ST black screen with white border

So here it is: /RESET and /HALT after reset. https://i.ibb.co/Mg8QFbY/Reset-Halt.gif As you can see /RESET goes low after approx. 7µs. The next low-phase of /RESET is triggered by TOS. Second instruction is a Reset instruction. http://info.sonicretro.org/SCHG:68000_Instruction_Set That is the reason...
by Arne
Sun Jan 19, 2020 9:15 pm
Forum: Hardware
Topic: Atari 520ST black screen with white border
Replies: 10
Views: 1228

Re: Atari 520ST black screen with white border

/RESET and /HALT should go high in conjunction after reset button was released. I will take a screenshot of my scope with these signals tomorrow.
Check the clock tree. Maybe MMU does not output 8MHz or does not receive 16Mhz from Shifter or....
by Arne
Sun Jan 19, 2020 5:44 pm
Forum: Hardware
Topic: Atari STFM dead
Replies: 17
Views: 2456

Re: Atari STFM dead

aszasza wrote:the one I used is actively driving the reset line high or low and it works just fine of course.

/RESET line is bi-directional :!: Think about it.
by Arne
Sun Jan 19, 2020 7:17 am
Forum: Hardware
Topic: Atari 520ST black screen with white border
Replies: 10
Views: 1228

Re: Atari 520ST black screen with white border

I forgot to mention: what about /RESET and /HALT on the CPU? These should go low when pressing the Reset button and then back to high. Is there activity on CPU's /AS, /UDS and /LDS lines when releasing the Reset button? CPU will try to read SP from address $0 first so it is a typical read access. Yo...
by Arne
Sat Jan 18, 2020 7:23 am
Forum: Hardware
Topic: Atari 520ST black screen with white border
Replies: 10
Views: 1228

Re: Atari 520ST black screen with white border

ROM2 on the GLUE is high. Is it constantly high - all the time? There should be at least four low pulses (CPU fetching 32bit SP and 32bit PC = four 16bit accesses). Check the PCB trace of /ROM2 and look at Glue's PLCC socket if that pin has contact. I have no SC1224 at hand. Try pulling all TOS ROM...
by Arne
Fri Jan 17, 2020 9:43 am
Forum: Hardware
Topic: Atari 520ST black screen with white border
Replies: 10
Views: 1228

Re: Atari 520ST black screen with white border

Gonna bring out the logic probe this weekend and check the DRAMs. Good idea. As it seems that all data lines are affected I suggest to look for unusual behaviour on /RAS0 (if it is a "real" 520 with 512KB) otherwise on /RAS1 if it got a memory upgrade using the 2nd bank. Additionally you ...
by Arne
Fri Jan 17, 2020 7:38 am
Forum: Hardware
Topic: Atari TT internal/external floppy issues
Replies: 5
Views: 924

Re: Atari TT internal/external floppy issues

Then I suggest to check the MO (Motor On) signal coming from FDC (pin 20), that runs to an inverter (7406 U405 pin 11) and exits it on pin 10 the same IC. Check the PCB tracks with a multimeter first when TT is powered off. With a FDD attached there needs to be a resistance of ~10KOhm between pin 10...

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