FPGA Replay Board

[psxphill]

As the Amiga sampling frequency may vary significantly but the output will not. A constant difference in frequency of course add another frequency, then there's aliasing etc.

I don't believe the Amiga sample rate does vary, all samples appear to be output relative to the colour clock.
 
http://blog.kebby.org/?p=11
 
http://eab.abime.net/coders-general/63227-low-level-workings-paula.html
 
3.58mhz is a little high to be outputting though. The Amiga will put that through some form of filter, even when the low pass filter is off.
 
From what I can tell the 2 bytes in the AUDxDAT register get output alternatively for 64 clocks, the audio changes when another 2 samples are loaded (either via dma or cpu). Which kinda sounds like it would cause a lot of noise artifacting, but apparently not (although paula does sound a bit crunchy at times).
 

You could do a SCSI-II controller in the FPGA (plenty of gates left), but I happen to have about 2000 53C80 chips sitting here to give me SCSI. SCSI is exclusively used by the Mac, and for the Mac emulation I will need SCSI support to access things like Syquest drives, CD-ROM drives, tape drives, etc.. all of the same stuff that is plugged into my A3000.

I would hope the Mac emulation will work without any real SCSI peripherals though, at that point you probably don't want to use a real 53C80 as you'd be limited to only having real peripherals or only having emulated ones. If you emulate the 53C80 then you can have a mixture of real and virtual peripherals, plus it would be nice if you could use the same interface for emulating any machine with SCSI whatever controller chip it uses.
 
Of course you can go ahead and make your own expansion board with a 53C80 if you like, but it is likely it will have a very small audience as everyone is likely to want the board with the real 68060 and the people who need an emulated SCSI controller chip will have to effectively redo the same work. While if we could persuade mike to just throw on some SCSI/IDE connectors (or even space for them) then it would meet everyone's needs (except your manufactured need of finding somewhere to put these 53C80 chips).

[psxphill]

(if it had HDMI would have been perfect).

Unfortunately HDMI is expensive to add. The video is easy to convert from DVI-D to HDMI as it's just the connector, but getting the audio in the correct format is not as simple. However a lot of DVI connectors on PC graphics cards include HDMI compatible audio as well, ATI seem to just put the interleaved video and audioover DVI-D.
 
http://www.mcscom.co.uk/live/index.php?route=product/product&product_id=22510
 
"With the correct hardware this adapter allows you to transmit high-definition digital audio from your PC using a single HDMI cable. Generic DVI-HDMI adapters do not support this function and only transmit the video signal."
 
What I don't know is what stops the standard cable from working, whether it's just a case of the graphics card detecting the special ATI dongle.
 
I believe NVidia also have an adapter, but they use a different method that involves SPDIF and are supposedly less compatible. I can't find a technical description of how that works either.
 
People selling adapters don't help http://www.ebay.co.uk/itm/Replacement-DVI-Male-to-HDMI-Female-Audio-Plug-Adapter-/390611645116?pt=UK_Sound_Vision_Other&hash=item5af244b2bc

[psxphill]

Full HDMI have more than just audio added into the standard. DVI is unencrypted video while full HDMI is encrypted to disallow people from just recording lossless video onto a BluRay burner.

I think you're talking about HDCP, which can also be used with DVI http://en.wikipedia.org/wiki/High-bandwidth_Digital_Content_Protection
 
You don't have to have HDCP for HDMI though, it's just that bluray software on windows will check to make sure it's being used. If no software checks that HDCP is enabled then it doesn't matter if it is or not. Some computer monitors don't support it, the only thing you can't do with those is play bluray movies (unless they also support VGA and you have a VGA output).
 

Hmmm doesn't the raspberry pi come with HDMI?

They probably paid the HDMI license fee. The chipset in the raspberry pi supports HDCP, but it's not ever enabled. HDCP only really works with closed source software, on windows the bluray software also makes sure the drivers are WHQL signed so you can't hack the driver to disable HDCP but tell the bluray software that it's enabled. It's unlikely anyone will ever run closed source bluray player software on a Raspberry Pi or an FPGA Arcade, so HDCP is not a concern.
 
 

What about one of these (expensive) adapters?
 
[URL]http://www.ebay.co.uk/itm/StarTech-com-DVI-to-HDMI-Video-Converter-with-Audio-Video-converter-black-/380549230284?pt=UK_Computing_Other_Computing_Networking&hash=item589a806ecc[/COLOR][/URL]

Yeah the expensive adapters will work, but at that price it would be cheaper for mike to pay the HDMI licensing cost.

[psxphill]

I am thinking about an add-on SCSI interface, either software driven through the FPGA or using a real 53C80. Everything for the Mac is SCSI based for external peripherals, so having SCSI is not an option for Mac emulation.

If you have a particular SCSI device you want to connect to it then you need SCSI connector (or at least a SCSI to USB/SATA/whatever converter), but whether that is for a mac emulator or you want to emulate an A1200 and hook it up as an IDE drive should be irrelevant. If the FPGA replay supported ATA/SATA then there should be no problem making devices connected to it appear to the emulated mac as a SCSI peripheral connected to a 53C80.
 
You shouldn't need a different expansion board and set of peripherals just because you want to emulate a mac or amiga or st etc. The idea is you can emulate a mac one minute and a cd32 the next, if you want to use real CD's on either then you shouldn't have to plug a different drive in. It would be terrible if trying to emulate an ST with an external drive required a new external board and an ACSI drive.
 
The majority of course will want to just emulate without any real peripherals and have them all virtualised from images on their SD card anyway, CD drives are likely to be the only real device most people would want to use. The majority would want to use a hard drive to store more images, not actually use the hard drive direct (although both options should be allowed).
 
 
 

The HDMI mode that allow HDMI+audio uses a different line coding. So the existing HDMI encoder chip on the FPGA Arcade can't be configured to enable audio.

That is a shame, those ATI DVI->HDMI converters would be a cheap way around the licensing issue if the hardware shipped as DVI but could be upgraded to generate DVI+audio later on by some unscrupulous individual.

[psxphill]

Yep, my mistake... referring to a 15KHz DB9<>DB15<>DVI adapter. Some of the arcade games (like Phoenix) use a 61 Hz (yes, really) refresh so I am trying every monitor/adapter I own to see what will sync.

Yeah arcade game refresh rates are all over the place because they had little to restrict them, they ended up with whatever came out easier in hardware.
 
Home computers were only better because they couldn't guarantee you'd be able to change h/v sync enough, but they generally weren't really NTSC/PAL compatible.
 
The mismatch between display refresh rate and the games refresh rate is a problem for emulation, in some ways it's better to change the actual speed of everything so the two match up. Although this means you need to pitch shift the audio, but this is much easier than trying to resample the video at a different refresh rate.

[psxphill]

To me, it's more amazing than the Amiga core (only because I have seen Amiga cores before, never a FPGA based arcade machine emulation).

This one has been out for a while.
 
http://arcade.gadgetfactory.net/
 
http://www.youtube.com/watch?v=YW-ybUw_Elk
 
This one is new... http://pipistrello.saanlima.com/index.php?title=Welcome_to_Pipistrello hdmi ftw (it can even sorta do 1080p http://hackaday.com/2013/03/08/pumping-1080p-video-out-of-an-fpga/)

[psxphill]

Slavery is an euphemism for capitalism here, imho.
Capitalism is killing us all.

Without capitalism we wouldn't have computers.

[psxphill]

more gates means better functionality

Only within the same architecture, Spartan 6 & Spartan 3E are different architecture. The Spartan 6 LX45 seems to be just a little more expensive than the Spartan 3E with 1.6M gates, while the Spartan 6 has less gates it has more units.
 
I don't know enough about the different FPGA architectures to determine which is better.
 
http://uk.rs-online.com/web/c/semiconductors/programmable-logic-circuits/fpgas/?sort-by=Number+of+Logic+Cells&sort-order=desc&view-type=List&applied-dimensions=4294511735,4294489143,4294489119,4294484685,4294508744,4294508738&lastAttributeSelectedBlock=4294958899&sort-option=Number+of+Logic+Cells

[psxphill]

Directly connecting the FPGA has it's own issues with signal quality at higher resolutions, the IO is not really up to the job. Let's see what the new generation FPGAs can do.
/MikeJ

The pipistrello will be interesting to watch, although I'd like to see something a bit more than 8 bit.
 
http://www.gadgetfactory.net/2013/07/spectrum-zx-with-hdmi-out-on-the-pipistrello/
 
Xilinx seem to be pushing HDMI now, all their evaluation boards seem to have them. I don't know what resolution their higher end FPGA's can achieve though.

[psxphill]

But what does physically generate the signals if the FPGA I/O isn't up to it?
 
Regarding HDMI at large it has the attributes of legal entrapment and should be avoided as much as possible. Ie don't use HDMI encoders, HDMI connectors, select players and TVs without it etc. Make use of DisplayPort and similar free video interfaces.

According to http://www.dream-multimedia-tv.de/board/index.php?page=Thread&threadID=12016
 
Dreambox DM8000 uses a http://mipt.cc:8080/index.php?title=BCM7400
As the HDMI encoder is embedded in the CPU and the board has a DVI output, then they may have argued that it doesn't need an HDMI license. However they might have paid one anyway, we don't know.
 
 

When I owned an original Dreambox DM800s, which is an HD box, it had a DVI connector on the back. It came with a DVI to HDMI cable and HAD audio. So I guess there is a way around it.

There is a solution, you use an HDMI compatible PHY. But the FPGA replay doesn't have one & it's a bit late to start thinking about adding one.

[psxphill]

Ok so can Spartan-6 LX FPGA make HDMI video+audio signals or is that "too hard" for it to accomplish?

The spectrum HDMI video I posted shows it can, the fpga isn't rated to 1080p but it seems with a wing and a prayer it seems to work.

[psxphill]

Actually pretty soon, I have hundreds of the damn things I need to get rid off.
Just want to make sure they work.
If you don't want the Amiga core you can have em now ...
/Mike

I'll take you up on that, they are upgradable right?

[psxphill]

If I use an adapter as in the picture below on a normal PAL TV (through HDMI, 50hz), will I get a picture without any problems?

You should get a picture with just a DVI-D to HDMI adapter.
 
AFAIK all the adapter will do is mix in the audio so you can use your TV's speakers (if it doesn't allow a separate audio input to be selected when using HDMI).
 
If your TV has a VGA input then that is another option.

[psxphill]

4. So if I use a DVI to HDMI from Ebay i will get screen tearing (like no Vsync effect?)

You shouldn't, what he means is that he's doing a convertor and so that the convertor doesn't add tearing he's doing it a line at a time.
 

Hmmm - so some games may work, others not? How will this affect games exactly.

He means some TV's will work, some won't. For OCS the timing is always the same, so if one game works they all should. If you're using ECS/AGA then you can change the timing, but I don't know if any games actually do.

[psxphill]

Since Norway is not yet in the European Community, effectively, you can pre-order without VAT at our shop but you'll certainly have to pay the norvegian VAT when it comes in the country.

Yeah when importing goods from a non EU country you pay VAT to your own government at the rate that they set, not to the country where you are buying it from at the rate they set. I don't know about Norway, but importing into the UK you will also be charged import duty and the courier will add their own price for presenting it to customs & VAT is charged on that too.
 
Goods sold within the EU have VAT applied at source at the rate set where they are sold (which doesn't have to be where they are shipped or invoiced from if you follow amazon's business model). It makes it annoying when you buy something from a country in the EU that has 20% VAT, but at least you don't get stung for the import duty and fee for presenting it to customs.
 
The VAT system for imports seems to be designed to dissuade individuals from importing as VAT registered companies can claim it back anyway.

[psxphill]

Yeah, countries like the UK... (UK VAT has been 20% since 2011)

Oh yeah, forgot about that we'd hiked ours. It's Sweden and Denmark with 25% that you need to watch out for.