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Author Topic: Enterprise HDMI Out (Read 7924 times)

Offline Saint

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Enterprise HDMI Out
« on: 2013.August.30. 10:37:02 »
I've been working on my first proper hardware project recently to get myself familiarised with VHDL and hardware design better (I still intend to return to doing an Enterprise on a chip one day!). I've just checked the Enterprise schematics, and it can also be used on the Enterprise -- it's an HDMI port add-on!

I found the biggest problem with old computers was attaching them to modern TV's and monitors. The picture through RF is terrible, and SCART isn't perfect, so I thought "how hard can it be to add HDMI?!". Apparently quite hard. Hehe. :lol:

I have written an HDMI encoder IP core which will output a 720x576p image directly from a little FPGA board with sound over HDMI. My early prototype has one bit of colour coming from the Atari ST shifter chip and being encoded into the HDMI stream. The picture is rubbish and you can barely tell what it is, but it's a working proof of concept!

I currently have a small batch of prototype PCB's being made in China which I should be able to get working properly with a full colour (or so I hope).

The great thing is, this will work with any computer which you can tap the RGB lines directly. The Enterprise has the 8 bits of colour data and sync signals coming out of the Nick chip to the LM1886, which is perfect for tapping.

The original thread can be found here: http://www.atari-forum.com/viewtopic.php?t=24684.

I hope to bring HDMI to all old machines eventually... :)

Offline Zozosoft

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Re: Enterprise HDMI Out
« Reply #1 on: 2013.August.30. 10:54:01 »
Very interesting idea!

Offline Zozosoft

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Re: Enterprise HDMI Out
« Reply #2 on: 2013.September.03. 12:04:09 »
When will you try it with the Enterprise?
« Last Edit: 2013.September.03. 13:38:08 by szipucsu »

Offline Saint

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Re: Enterprise HDMI Out
« Reply #3 on: 2013.September.03. 12:22:37 »
I'm waiting on my PCB's from China at the moment, they will be about 4 weeks yet. When they arrive, the first thing to do is to get it working with my Atari ST motherboard. Once this is working I'll start thinking about other computers, the Enterprise being the first now I have my "spare" Enterprise 64 to hardware mod, assuming it works when I get my replacement parts through. Although if Nick or Dave have failed on this machine, it does give me a good excuse to start thinking about a PLD replacement... :)

The Enterprise will be a little more difficult for the HDMI out as the video is so configurable. With the ST you have a fixed sync pattern and I can actually lock the CPU clock and the video clock precisely in sync. The Enterprise is going to require a bit more thought... :ds_icon_cheesygrin:

Offline Tuby128

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Re: Enterprise HDMI Out
« Reply #4 on: 2013.October.01. 03:05:15 »
Hello Mr,
 What kind of circuit are you going to use to this project?
 I am courious, when and who will first invent the one chip EP computer.

Offline Saint

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Re: Enterprise HDMI Out
« Reply #5 on: 2013.October.01. 10:11:48 »
If you have a look at the link to the Atari forum it outlines how the HDMI out works using an FPGA.

I started looking at the "one chip" Enterprise a year or so ago, but due to lack of time and knowledge I didn't get all that far. I had something of the Nick chip running, but I am quite new to hardware design.

At the moment I'm working on other Enterprise hardware (see the SD card interface and internal memory expansion), but will return to the one chip Enterprise one day.

The next project to be finished will be the 512KB internal memory expansion. I'm just waiting on the PCB's and GAL chips from China to build one up. Hopefully my PCB layout will work... :)

Offline Tuby128

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Re: Enterprise HDMI Out
« Reply #6 on: 2013.October.01. 21:38:41 »
Thank you for your explanation, it is always fantastic hearing about some new development, which based on the EP.
My question is aimed to inquire exactly which type of IC you use to achieve your developement? As answer manufacturer and chip-family would be enough. For instance I use Altera products, and I am very satisfied with the Cyclone family. I like MAX II as well, this comprises a flash gate-memory, a big advantage that after power-off it contains the last config, but for development is too slow, because flash programming needs more time. The Cyclone series doesn't have flash memory, if you intend to use your config later, you must use an additional IC, but for development is excellent, because the configuration is about 3 sec. Additionally it has a lot of built-in memory (ram), and it's very fast. and able to dual-port (Two addresses and two data ports, which can acces to the same memory at the same time). Furthermore it has several multiplication modul, with these you can save a lot of clock-pulse if you make a complex calculation.
 And my favourite, it has a differential output. Nowdays it is the best way to communicate with another IC in high-speed and without any disturbance. I could be endless writing about this theme, but unhappily I have to work tomorrow.
« Last Edit: 2013.October.02. 12:49:42 by szipucsu »

Offline Saint

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Re: Enterprise HDMI Out
« Reply #7 on: 2013.October.01. 22:20:11 »
For the HDMI FPGA I use a Altera Cyclone II mini development board from China off eBay (which contains a config prom). I have been able to drive the HDMI TMDS lines using the LVDS outputs of the Cyclone successfully, although they are really incompatible signal levels. I think there are some "signal sanitisation" chips in monitors which help clean up the signal. I have also had to use a 3.3v<>5v translator chip to convert the signal level for the FPGA.

For the SD card interface, I have the Altera MAX300A chips in mind as they are flash based, as you say, 5v tolerant, and cheap! I've not used them before, but they look good.

Offline Tuby128

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Re: Enterprise HDMI Out
« Reply #8 on: 2013.October.02. 16:39:34 »
I am very happy that we speak the same technical language. Have you ever thought about visit Hungary, and speak with EP friends about this beautiful treasure we have?

Offline Zozosoft

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Re: Enterprise HDMI Out
« Reply #9 on: 2013.October.29. 11:31:42 »
Is there any news about your HDMI project?
« Last Edit: 2013.October.29. 11:40:44 by szipucsu »

Offline Saint

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Re: Enterprise HDMI Out
« Reply #10 on: 2013.October.29. 14:19:58 »
Quote from: Zozosoft
Is there any news about your HDMI project?
No, I've not done any further work on the HDMI project since starting on the Enterprise RAM expansion. I'll get back to it one day. :)