Search found 2382 matches

by ijor
Sat Jan 13, 2018 11:09 pm
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

It WORKS. It does seem as if I need to time it to actual RESET very accurately though. I'm not sure why? Congratulations Ijor - yet another feather in your hat! :D On one single power cycle and three RESETs I've gone through WS1, WS3, WS3 and WS4. :) :) So glad it works. Jaja Not sure why you need ...
by ijor
Fri Jan 12, 2018 12:47 pm
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 4245

Re: STFM to DVI/HDMI project

Haha, Quartus has about three trillion buttons I've never clicked on... :wink: I see :) You'll soon learn that the more internal RAM available you have, the more useful SignalTap is. I realize it is not easy to replace the FPGA, but it is recommended to debug with a larger FPGA so that you have lot...
by ijor
Fri Jan 12, 2018 12:40 pm
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 4245

Re: STFM to DVI/HDMI project

Yeah it does sound strange. However, while the Mega ST schematics are from 1986, you can find the part number also in the Mega STE service manual from 1991: U17 C025914 IC CUSTOM SHIFTER U31 or C101608 IC CUSTOM FULL SHIFTER (w/D/A) U31 STF (Non STE) parts on Mega STE service manual ??? Where do yo...
by ijor
Fri Jan 12, 2018 10:58 am
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 4245

Re: STFM to DVI/HDMI project

Spectrum 512 works well now and also an overscan test program that Troed sent to me that displays a static image with all borders extended. Nice :) I haven't got a LA, just a 2-channel 'scope. Moving demos are hard to follow. I guess you know that the FPGA has some sort of integrated LA (SignalTap)...
by ijor
Fri Jan 12, 2018 12:41 am
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 4245

Re: STFM to DVI/HDMI project

Smonson wrote:But right now, I want to finish this project before moving on to another one. Maybe someone else will do it first :)


So how is this project going, Smonson? Any news? :)

Did you try what I recommended? Enhancing/fixing the simple model that should work with almost all overscan programs?
by ijor
Fri Jan 12, 2018 12:38 am
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 4245

Re: STFM to DVI/HDMI project

Apparently there are three different Shifters, with slightly different motherboards, looking at the Mega ST schematics at least. One of the Shifter models does not output 3 bits RGB each, but has an internal version of the resistor grid and outputs the analog R,G,B signals directly. C101608 would b...
by ijor
Tue Jan 09, 2018 12:15 am
Forum: The Atari 8bit corner
Topic: If then else bypass
Replies: 10
Views: 472

Re: If then else bypass

MrPixel wrote:i will try that now. thank you. also, is there a way to save created games to .Tap or cart? i'm using WinAtari800Plus


You can save Basic programs to tape or to disk, if that's what you mean, but not to easy to cart. Btw, Atari800WinPlus is very outdated. I'd recommend switching to Altirra.
by ijor
Tue Jan 09, 2018 12:13 am
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

the LOAD pulses are 5 32MHz clock cycles in this trace. Unless that's strange since they come from 16MHz MMU ... That's correct. It is 2 and a half cycles on the OLD MMU versions. It combines the output of two flip flops working at the opposite edge of the clock to get half cycle resolution. Btw, t...
by ijor
Mon Jan 08, 2018 6:35 pm
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

Well the B2 trace is of the output blue bit 2 so any Shifter wakeup should be visible there? (Come to think of it, maybe I should see if I can clock the LA at 32MHz while still accurately detecting the other signals) You might get an estimate. But without comparing with the output at med rez, is no...
by ijor
Mon Jan 08, 2018 5:56 pm
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

Interesting. Looking at the PIN schematics at https://www.exxoshost.co.uk/forum/viewtopic.php?f=31&t=149 the pin between /SNDCS and /MFPCS is named GND on the DIP version and TEST on SMD :) However, looking at the Mega ST schematic pin 52 is indeed marked as "TEST", and wired to GND. ...
by ijor
Mon Jan 08, 2018 5:04 pm
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

Attached are full frames of a regular low resolution screen in WS1, WS2 and WS3. Just great. Many thanks :) (I really need to build that automatic circuit that will power cycle until a set WS .. ). Well, as I commented some time ago in other thread, it is possible (at least in theory) to build a sm...
by ijor
Mon Jan 08, 2018 12:26 am
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

Anyway, for the cases where only relation to CPU clock is of interest I've now managed to clock my LA from the CPU clock, which means I can stream all other signals at 50MHz and capture as many frames as I want. Sync capture is great. But if you can and you still get one full frame, try using the 1...
by ijor
Sun Jan 07, 2018 7:37 pm
Forum: MiSTer
Topic: SDRAM+SRAM board (only concept for now)
Replies: 12
Views: 544

Re: SDRAM+SRAM board (only concept for now)

65MHz*3 = 195MHz.. Haha, better than Async SRAM ))))) It's 3 cycles only for the standard pipelined version, and only when switching bus direction. The flow through version has two cycles latency. And the NoBT/ZBT parts work at two cycles pipelined or single cycle flow through same as Async. Flow t...
by ijor
Sun Jan 07, 2018 7:22 pm
Forum: MiSTer
Topic: MISTer on DE0-nano-SoCKit?
Replies: 81
Views: 3481

Re: MISTer on DE0-nano-SoCKit?

Out of curiosity - could you please describe (or point me to some tutorial) how to calculate PLL phase shifts and so one. Tried to go through altera tutorials on TimeQuest - didn't find any practical benefit yet. Just calculate the center of the waveform's eye: - Compile the core without any PLL sh...
by ijor
Sun Jan 07, 2018 1:23 pm
Forum: MiSTer
Topic: SDRAM+SRAM board (only concept for now)
Replies: 12
Views: 544

Re: SDRAM+SRAM board (only concept for now)

Sorgelig wrote:Good luck to find SSRAM in TSOP or similar soldering iron friendly package and make it run at 200MHz on MiSTer module ;)


200 MHz perhaps not, but technically there is no reason why it shouldn't run, at least, as fast as SDRAM.
by ijor
Sun Jan 07, 2018 1:18 pm
Forum: Coding
Topic: ST Chipset decap
Replies: 125
Views: 22351

Re: ST Chipset decap

Steven Seagal wrote:Are you saying that the GLUE "M2CLOCK" can awake at an arbitrary 0-15 tick (~32mhz) on the STF relative to DCYC, and not always on the same n, n+4, n+8 or n+12 tick?


No, it isn't that bad either. It will (or should) trigger always within the same cycle.
by ijor
Sat Jan 06, 2018 5:12 pm
Forum: MiSTer
Topic: SDRAM+SRAM board (only concept for now)
Replies: 12
Views: 544

Re: SDRAM+SRAM board (only concept for now)

Because of talks here and there about SRAM module, i've decided to try to combine both SDRAM and SRAM. Good news - it works! Not so good news - max speed i can achieve is 65MHz instead of theoretical 100MHz. 65MHz is still not bad for pure random access. SDRAM allows only 1/8 speed of its clock, so...
by ijor
Sat Jan 06, 2018 5:06 pm
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: LA traces on interesting video signals

I've currently hooked up 8 signals: /LOAD, 8MHz CPU, 16MHz Shifter, DE, HSYNC, VSYNC, Blue bit 2 and /BLANK ... Unfortunately it seems the built in RLE compression of the LA won't help out in this case since the signals change state too often. I'm only able to acquire ~51000-56000 samples at 100MHz...
by ijor
Sat Jan 06, 2018 2:39 am
Forum: Coding
Topic: ST Chipset decap
Replies: 125
Views: 22351

Re: ST Chipset decap

DL latencies apparently are 3-6 cycles, or 12-24 32mhz ticks, precisely, not, say, 3.25 cycles for WS2. I still don't see your point. Hardware is never that precise. Of course that is not N cycles exactly, and the instrument used to measure has its own limitations anyway. But why you do care? This ...
by ijor
Fri Jan 05, 2018 1:10 am
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: ST Chipset decap

Thx, up to now only one such graph was "generally" available I think, and less precise. It seems to be multiples of 8mhz cycles too, I thought there could be some fraction. There should be traces I posted long ago. They didn't include the end of the line though, only the start. I'm not su...
by ijor
Fri Jan 05, 2018 1:02 am
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: ST Chipset decap

Ah, great to hear you already have them :) My Mega ST has the regular -38 Shifter, but it's socketed so I could always get an IMP (atarifreakz has them) and play around with. I guess it would need to be the R,G,B outputs that would have to be timed to see Shifter wakeups? Well, if it is not too muc...
by ijor
Thu Jan 04, 2018 2:04 am
Forum: Hardware
Topic: LA traces on interesting video signals
Replies: 27
Views: 846

Re: ST Chipset decap

What signals do you want captured? A while back I decided it would be fun to have an LA so I bought one. I've captured WS1 and WS2 from my Mega ST below ... Many thanks Troed. But to be honest, I got full captures of all the wake states since the message you quoted. :) At this time I might be more ...
by ijor
Wed Jan 03, 2018 1:23 am
Forum: Coding
Topic: ST Chipset decap
Replies: 125
Views: 22351

Re: ST Chipset decap

First mission of the year, count pixels! I did on the following frames, the scroll is in fact precisely 4 pixels between each frame, there's no 3 pixel scroll between some frames like I thought: ... In summary (including DE, when the pixel clock starts, and # words in the Shifter at first reload): ...
by ijor
Sun Dec 31, 2017 6:52 pm
Forum: Coding
Topic: ST Chipset decap
Replies: 125
Views: 22351

Re: ST Chipset decap

Here are traces of a low level emulation of the 4bit scroll and a table. ... ST-connexion 4 bit scroller ... I'm not asking the theory but if we're sure that each step is 4 pixels, because on an experimental Steem build the scroll apparently works but delivers the traces I posted, showing shifts of...
by ijor
Sun Dec 31, 2017 2:26 pm
Forum: Coding
Topic: ST Chipset decap
Replies: 125
Views: 22351

Re: ST Chipset decap

While I've only done some brief tests, the fact that setting both bits in RES is read as HI by GLUE and stops the clock mux in the Shifter has allowed me to get my "stabilizer-less" fullscreen scanline as used in {Closure} to display correctly with both my code paths in WS2. Recap: I got ...

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