Search found 92 matches

by Smonson
Thu Jul 12, 2018 9:24 am
Forum: Coding
Topic: Different SHIFTER versions
Replies: 35
Views: 1692

Re: Different SHIFTER versions

It also starts after the 5th LOAD in Troed's LE captures.

Image
by Smonson
Fri Jul 06, 2018 12:18 am
Forum: Coding
Topic: Different SHIFTER versions
Replies: 35
Views: 1692

Re: Different SHIFTER versions

It sounds like this could explain why I've never been able to see that sync scroll effect work on the FPGA model. Very interesting indeed!
by Smonson
Mon Jul 02, 2018 12:30 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

That's a bit out of my price range.
by Smonson
Sun Jul 01, 2018 11:50 pm
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

If by "compatible HDMI capture hardware" you mean a mobile phone camera, I can do that tonight :D
by Smonson
Sun Jul 01, 2018 4:33 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

Yes, that's what I said earlier. You might need to compensate with the pixel counter start value. Both determine the exact palette lookup timing. Not sure if I would call that a shift register, it is more that the palette index selection according to the resolution, and the palette lookup are both ...
by Smonson
Sat Jun 30, 2018 2:35 pm
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

So are bits shifted out of the RRs are going into a shift register before hitting the palette lookup? It affects spectrum 512, so I'd rather have it working.
by Smonson
Sat Jun 30, 2018 10:12 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

By the way, I'll keep this on github to avoid making a new post every time the code gets updated. https://github.com/smonson78/st-shifter-verilog
by Smonson
Sat Jun 30, 2018 9:33 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

An interesting observation: I downloaded DSView to check Troed's captured LA traces and noticed that the pixels on the real shifter are being generated after the 5th shifter load. That is about 3 pixels later than the simulated result. Same wakestate (1), same setting for pixel_counter's initial val...
by Smonson
Thu Jun 28, 2018 5:31 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

I got modelsim to work in Quartus 18 in the end, but I find it painful to use. I tried gtkwave today though and it's like magic. Obviously it's basically a toy in comparison to modelsim, but it's literally ten thousand times faster (over 90 seconds vs 6 milliseconds to refresh after editing the veri...
by Smonson
Wed Jun 27, 2018 12:53 pm
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

No. It is just a warning that a clock mux was detected. If you then go to the manual it would elaborate why that kind of clock mux is not recommended. The manual's another thing that doesn't work for me in Quartus 13, but I read up on glitch-free clock multiplexers earlier and realised that it's no...
by Smonson
Wed Jun 27, 2018 12:34 pm
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

On 64-bit linux. Yeah, I've got all the library stuff fixed, it is just a problem starting ModelSim itself. It's good to hear that it does work for you mfro, perhaps it is fixable after all. ModelSim-Altera was not found. Please install ModelSim-Altera which is included with the Quartus II installer...
by Smonson
Wed Jun 27, 2018 8:16 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

Well, I've spent an hour and a half looking at the simulation function in Quartus, and it seems that version 13 (the last version that supports the Cyclone-II) is buggy and can't run ModelSim. A bit of a dead end unfortunately.
by Smonson
Wed Jun 27, 2018 6:25 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

That should not happen, they never overlap except on RESET. They are, at least, one 16MHz cycle apart (so more than one 32 MHz cycle). May be you used something like this: wire reset = load_state == `LOW && !cs; That is not correct because load_state is registered and cs is not (Did I menti...
by Smonson
Wed Jun 27, 2018 6:10 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

This is fairly stable now, so I'm sharing the verilog model that I'm using. Spectrum 512 works as long as the pixel count initial value is changed from 4 to 2. This is probably because you are missing some pipeline cycles between the shift array and the palette lookup. But note that there is no ide...
by Smonson
Wed Jun 27, 2018 3:02 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

Thanks for the comments Ijor. I'll reply in detail later when I have a PC in front of me, , but as for this one... wire reset = load_state == `RISING && !cs; Reset is whenever both signals are asserted (low), not just on the raising edge of LOAD. Might produce a slightly different behavior. ...
by Smonson
Wed Jun 27, 2018 12:51 am
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

Thanks Ijor!
by Smonson
Tue Jun 26, 2018 3:50 pm
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

No problem, it's basically Ijor's work laid out in verilog. Apart from the bugs, those are all my own work :lol:
by Smonson
Tue Jun 26, 2018 2:54 pm
Forum: Coding
Topic: SHIFTER reimplementation on FPGA
Replies: 45
Views: 4081

Re: SHIFTER reimplementation on FPGA

This is fairly stable now, so I'm sharing the verilog model that I'm using. Spectrum 512 works as long as the pixel count initial value is changed from 4 to 2. // Shifter model based on Ijor's reverse-engineering. `define RISING 2'b01 `define FALLING 2'b10 `define HIGH 2'b11 `define LOW 2'b00 module...
by Smonson
Tue Jan 16, 2018 7:57 am
Forum: Chat forum [ENG]
Topic: Surviving STs
Replies: 32
Views: 3701

Re: Surviving STs

If you want an old computer from ebay, but don't like to pay high prices, my favourite technique is to buy several totally broken ones and assemble all the good parts together into one working computer.
by Smonson
Mon Jan 15, 2018 8:22 am
Forum: Chat forum [ENG]
Topic: Very first computer
Replies: 58
Views: 5891

Re: Very first computer

Microbee by Applied Technology Pty Ltd c. 1982, as made famous by Hackerman

Image

My dad built it from a kit!
by Smonson
Fri Jan 12, 2018 2:33 pm
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 7640

Re: STFM to DVI/HDMI project

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 lots of internal RAM. Altera provides what they call "Vertical Migration"...
by Smonson
Fri Jan 12, 2018 11:19 am
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 7640

Re: STFM to DVI/HDMI project

ijor wrote:I guess you know that the FPGA has some sort of integrated LA (SignalTap) that is invaluable for debugging.


Haha, Quartus has about three trillion buttons I've never clicked on... :wink:
by Smonson
Fri Jan 12, 2018 8:25 am
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 7640

Re: STFM to DVI/HDMI project

I didn't, because of a lack of free time, but I have fixed a couple of bugs since last progress post. 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. Static test programs like that are useful because I use a ...
by Smonson
Thu Jan 11, 2018 9:55 pm
Forum: Hardware
Topic: STFM to DVI/HDMI project
Replies: 78
Views: 7640

Re: STFM to DVI/HDMI project

Regarding that, it's also a possibility to do so, but I initially envisaged this method being simpler. I think that I was wrong about that, and so I might try to make a board that reads the RGB values from the shifter's pins and leaves the shifter in place (this will work better on STE too). But rig...

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