Atom Video to HDMI Adapter

discussion of games, software, hardware & emulators relating to the Acorn Atom and Acorn System machines.
User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Mon May 13, 2019 6:54 pm

sparkyhall wrote:
Mon May 13, 2019 6:38 pm
You're spot on, TV was set to 4:3, now I have set it to 16:9 it looks much better.
If you have an aspect ratio called ("Screen Fit") that might look even better, as it turns off any scaling in the Samsung TV.

You could also try setting Interpolation to "Off (Sharp)" in the Atom Video to HDMI Adapter menu. A reboot will be required after that.

Those two settings combined should result in a very sharp image.

Dave

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Mon May 13, 2019 7:25 pm

hoglet wrote:
Mon May 13, 2019 5:53 pm
I've just pushed another Atom CPLD version (v2.4) that adjusts the colour sampling point so the optimal value is back in the 0-7 range. This means the previous profile should work unchanged. So please give that a try.
That seems to be OK now thanks.

BTW one slight flaw with the Atom design is that you have to dismantle the thing to get the SD card out to read screencapped images!
Have you tried booting from the micro USB port instead of the SD card as that could be accessed externally with an appropriate hole in the case.

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Mon May 13, 2019 7:38 pm

IanB wrote:
Mon May 13, 2019 7:25 pm
BTW one slight flaw with the Atom design is that you have to dismantle the thing to get the SD card out to read screencapped images!
Yeh, I only realized that quite late in the day. :(

I did consider moving the Pi over to the edge of the main board, but the corner posts get in the way, and would in most cases.

We need to get Wi-Fi working on the Pi Zero W.
IanB wrote:
Mon May 13, 2019 7:25 pm
Have you tried booting from the micro USB port instead of the SD card as that could be accessed externally with an appropriate hole in the case.
I've not tried booting from USB Storage.

But I have tried booting from a USB connected server which I think emulates USB storage (running rpiboot):
https://github.com/raspberrypi/usbboot

I think the SD Card driver we use is very much specific to the SD Card, and a different driver would be needed for USB Storage, possibly this one:
https://github.com/rsta2/uspi

That's quite a bit of work.

Dave
Last edited by hoglet on Mon May 13, 2019 7:40 pm, edited 2 times in total.

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Mon May 13, 2019 8:10 pm

hoglet wrote:
Mon May 13, 2019 7:38 pm
I did consider moving the Pi over to the edge of the main board, but the corner posts get in the way, and would in most cases.
Perhaps something like this is the answer:

https://www.modmypi.com/raspberry-pi/ac ... sion-cable

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Mon May 13, 2019 8:47 pm

IanB wrote:
Mon May 13, 2019 8:10 pm
Perhaps something like this is the answer:

https://www.modmypi.com/raspberry-pi/ac ... sion-cable
Nice find... I didn't know these existed.

There are some other types on eBay.

This one is a bit shorter (25cm), and might be easier to mount in a case slot.
https://www.ebay.co.uk/itm/TF-Micro-SD- ... 3543615727
(although that one is to a full size SD Card)
Last edited by hoglet on Mon May 13, 2019 9:04 pm, edited 1 time in total.

User avatar
Elminster
Posts: 3422
Joined: Wed Jun 20, 2012 8:09 am
Location: Essex, UK
Contact:

Re: Atom Video to HDMI Adapter

Post by Elminster » Mon May 13, 2019 9:09 pm

IanB wrote:
Mon May 13, 2019 8:10 pm
hoglet wrote:
Mon May 13, 2019 7:38 pm
I did consider moving the Pi over to the edge of the main board, but the corner posts get in the way, and would in most cases.
Perhaps something like this is the answer:

https://www.modmypi.com/raspberry-pi/ac ... sion-cable
I was looking for something like that a year or so ago for another project. I gave up as no one seemed to have one for sale at the time. I shall have to dig out the old project now.

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Tue May 14, 2019 5:39 pm

Hi all,

Time for another update :D

I got the new Noise Killer boards back this morning (plus the second batch of each of the other boards).

To recap, this latest version changes three things:
1. Fixed an error with two signals (VDG and NRDS) being swapped on a header
2. Improve the design so that it's reliable with 74HCT parts
3. Remove the superfluous noise-killer disable input

Here's a photo of one built up and installed:
IMG_1675.JPG
As you can see, it's populated entirely with 74HCT parts, and initial testing indicates that works just fine, and that there is plenty of timing margin.

One late change to the parts list: R2 had changed from 270R to 1K0 to give a ~75ns long write pulse, which should be good for operation at 4MHz (if the rest of your Atom is up to that). I've updated the schematic and BOM to reflect this.

Anyway, I was about to post a message to the forum saying everything is great when in some further testing I hit a small snaglet.

With certain text screens I was still seeing some kind of screen noise:
capture5.png
capture6.png
As this noise is appearing as red flecks, it looks like something is adding noise to one of the colour difference signals.

And indeed that's what was happening. Here's what PA looked like when it reached the HDMI adaptor board:
IMG_1669.JPG
The top signal is PA (on a scale of 200mV/division). The nasty spikes are clearly the result of crosstalk from another near-by signal. Now, the HDMI adapter has some digital filtering in the CPLD to make it more resilient to noise like this. But in this case that's clearly not sufficient.

The bottom signal is what I think is the culprit: Video Data 7 (VD7) into the 6847 (on a scale of 2V/division). I think this must always have been present to some extent. But the device driving this signal is now a 74HCT part. That has quite fast edges and a full 5V rail-to-rail swing. Both of those things make crosstalk worse.

To verify this, I replaced the 74HCT573 with a 74ALS573 (which is a bit slower) and the result was less crosstalk:
IMG_1670.JPG
In fact, as this stage the red noise on the test screen actually went away,

If you look at the Atom Schematic, it becomes apparent why VD7 is such a problem:
Selection_024.png
This data line, and only this data line, is output to PL4 (as the INV signal). So the crosstalk is happening on the cable connecting the Atom to the HDMI Adapter.

Anyway, the fix is really simple. This signal is unused by the HDMI Adapter, so cut pin 4 of the cable, as close to the Atom as possible:
IMG_1674.JPG
The result is greatly reduced crosstalk, even with the HCT part:
IMG_1671.JPG
As one final test, I've made up a 1M long cable between the Atom and the HDMI Adapter, and that seems to work perfectly.

I'm pretty happy with this outcome, so I'll be sending people who have requested board a PM shortly.

Dave

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Wed May 15, 2019 3:33 pm

hoglet wrote:
Tue May 14, 2019 5:39 pm
Anyway, the fix is really simple. This signal is unused by the HDMI Adapter, so cut pin 4 of the cable, as close to the Atom as possible:
Looks good, nice bit of diagnostic work there Dave.

User avatar
-B-
Posts: 117
Joined: Wed Nov 26, 2014 11:54 am
Location: Noordwijk ZH (NL) / Durham (UK)
Contact:

Re: Atom Video to HDMI Adapter

Post by -B- » Wed May 15, 2019 8:11 pm

My programmer finally arrived :D

But, I have a problem with the programmimng...

Everything goes as per the instructions until I get to...
An "Auto Assign Configuration Files" dialog box will come up, click [Yes].

I click yes and the egg timer comes up for a few seconds then Impact closes.

Any ideas?

Neil.

Edit: I declined the Winpcap install during installation.
Last edited by -B- on Wed May 15, 2019 8:18 pm, edited 1 time in total.
Atom | BBC Model A | BBC Model B | Electron | Olivetti PC128S.

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Wed May 15, 2019 9:26 pm

-B- wrote:
Wed May 15, 2019 8:11 pm
Everything goes as per the instructions until I get to...
An "Auto Assign Configuration Files" dialog box will come up, click [Yes].
That's almost certainly a software issue.

What OS are you running?

32-bit or 64-bit?

What version of the Xilinx software?

Did the boundary scan detect the correct device?

It might be worth answering no, and then you can try to manually assign the JEDEC file. But I expect this will crash as well.

Dave
Last edited by hoglet on Wed May 15, 2019 9:30 pm, edited 3 times in total.

User avatar
-B-
Posts: 117
Joined: Wed Nov 26, 2014 11:54 am
Location: Noordwijk ZH (NL) / Durham (UK)
Contact:

Re: Atom Video to HDMI Adapter

Post by -B- » Wed May 15, 2019 9:56 pm

I’ve given up for tonight, I have an early flight in the morning.

It’s Windows 10 64 bit.

I think it’s 14.7 of the ISE design suite with v13.1 of iMPACT. I installed it from the disc that came with the programmer as the Xilinx web site were asking a lot of questions before letting me download.

Boundary scan detected the correct device and it turned green after I clicked [yes] then it shut down after a few seconds. I could not right or left click on anything during those seconds.

I tried clicking [no] and then clicked the icon to assign a file but it shut down in the same way.

I’m on a business trip for 2 days so it will have to wait until Saturday now but, everyone feel free to share your thoughts or experiences with this software in case it helps me with the issue.

Neil.
Atom | BBC Model A | BBC Model B | Electron | Olivetti PC128S.

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Thu May 16, 2019 11:05 pm

hoglet wrote:
Mon May 13, 2019 10:03 am
IanB wrote:
Mon May 13, 2019 1:43 am
However, a better solution would be to auto adjust the profile capture area to compensate for different monitor resolutions so I will investigate if that's feasible.
That would make a useful additional scaling option.
I've got that working now as a switchable option and I also fixed a scaling bug with 4:3 interpolated scaling when a double width frame buffer was used (such as the Atom_CPLD profile)

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Fri May 17, 2019 8:47 pm

hoglet wrote:
Tue May 14, 2019 5:39 pm
I'm pretty happy with this outcome, so I'll be sending people who have requested board a PM shortly.
I built up my board and it works, here's the before and after with your noise test program:

Noise killer disabled:
nk-off.jpg


Noise killer enabled:
nk-on.jpg

Another successful project Dave =D>

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Fri May 17, 2019 8:53 pm

IanB wrote:
Fri May 17, 2019 8:47 pm
Another successful project Dave =D>
Glad it's working for you Ian.

The screen shot with the noise killer disabled looks worse than I've ever seen before. Do you get a sensible display when the killer test program is not running, or is it like that all the time?

Dave
Last edited by hoglet on Fri May 17, 2019 8:55 pm, edited 1 time in total.

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Fri May 17, 2019 9:03 pm

hoglet wrote:
Fri May 17, 2019 8:53 pm
The screen shot with the noise killer disabled looks worse than I've ever seen before. Do you get a sensible display when the killer test program is not running, or is it like that all the time?
It's probably due to a relatively long exposure by the camera, it doesn't look quite that bad in real life and the text is discernable.
I get a sensible display when the test program is not running and noise killer disabled.

Edit:
Here's a shorter exposure using flash:
flash.jpg
Last edited by IanB on Fri May 17, 2019 9:11 pm, edited 3 times in total.

User avatar
-B-
Posts: 117
Joined: Wed Nov 26, 2014 11:54 am
Location: Noordwijk ZH (NL) / Durham (UK)
Contact:

Re: Atom Video to HDMI Adapter

Post by -B- » Sun May 19, 2019 1:35 am

8K video RAM and noise killer board received today, built and working...

1791B5ED-4820-4F3F-909A-8849937417B2.jpeg
FB852D8D-F1DB-400F-98AE-44DB1056C5EA.jpeg
Many thanks to @hoglet.
Atom | BBC Model A | BBC Model B | Electron | Olivetti PC128S.

User avatar
Elminster
Posts: 3422
Joined: Wed Jun 20, 2012 8:09 am
Location: Essex, UK
Contact:

Re: Atom Video to HDMI Adapter

Post by Elminster » Sun May 19, 2019 8:53 am

[-X

I just ordered parts for atom RGB, 2 more beeb RGB, noise killer, 1mhz fpga board. And parts came to nearly £200. I think Dave is going to bankrupt me.

User avatar
-B-
Posts: 117
Joined: Wed Nov 26, 2014 11:54 am
Location: Noordwijk ZH (NL) / Durham (UK)
Contact:

Re: Atom Video to HDMI Adapter

Post by -B- » Sun May 19, 2019 3:42 pm

So, after uninstalling the version of the Xilinx ISE software that came with the programmer, signing up to Xilinx and downloading the latest VM version, I could not get the USB devices working. So I uninstalled that, looked at some youtube videos on the subject and decided to install the Windows 7/XP/Server version, but only the WebPack, and I finally managed to program my CPLD!

Many thanks to hoglet for this wonderful board.

I have attached some pictures but they don't do any justice to the actual quality of the output - I'm not the best photographer...

IMG_4492.jpeg
IMG_4493.jpeg
IMG_4486.jpeg
IMG_4488.jpeg

Neil.
Atom | BBC Model A | BBC Model B | Electron | Olivetti PC128S.

User avatar
-B-
Posts: 117
Joined: Wed Nov 26, 2014 11:54 am
Location: Noordwijk ZH (NL) / Durham (UK)
Contact:

Re: Atom Video to HDMI Adapter

Post by -B- » Sun May 19, 2019 10:08 pm

Hi Dave,
I have adjusted the video to HDMI board using the colour test program.
But the manic Miner start screen (moving letters see previous post) are red and yellow when Kees’ YouTube video also shows orange and blue.
I have VIA 6522 installed. Is there something else?
Can you reproduce it?

Neil.
Atom | BBC Model A | BBC Model B | Electron | Olivetti PC128S.

User avatar
oss003
Posts: 2960
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Atom Video to HDMI Adapter

Post by oss003 » Mon May 20, 2019 6:23 am

-B- wrote:
Sun May 19, 2019 10:08 pm
Hi Dave,
I have adjusted the video to HDMI board using the colour test program.
But the manic Miner start screen (moving letters see previous post) are red and yellow when Kees’ YouTube video also shows orange and blue.
I have VIA 6522 installed. Is there something else?
Can you reproduce it?

Neil.
Can you check if LK2 is in to enable the IRQ?

Greetings
Kees
Attachments
LK2.png

User avatar
-B-
Posts: 117
Joined: Wed Nov 26, 2014 11:54 am
Location: Noordwijk ZH (NL) / Durham (UK)
Contact:

Re: Atom Video to HDMI Adapter

Post by -B- » Mon May 20, 2019 4:04 pm

Yes, LK2 was the culprit!

Thanks Kees.

B9C85EDC-21A4-49BB-9090-D4B16A601C7B.jpeg
Atom | BBC Model A | BBC Model B | Electron | Olivetti PC128S.

User avatar
anightin
Posts: 137
Joined: Thu Aug 23, 2018 1:03 pm
Location: Cambridge UK
Contact:

Re: Atom Video to HDMI Adapter

Post by anightin » Wed May 22, 2019 7:12 pm

Hi Folks,

Finally finished assembling and got this on first power up:
IMG_3521.jpeg
IMG_3520.jpeg
Auto calibration counts up to 15 with about 1200 errors

Any clues of what debug steps I need to follow?

I haven't touched the cmdline.txt or config.txt files yet on the SD card BTW

Many thanks

Andy
Last edited by anightin on Wed May 22, 2019 7:18 pm, edited 2 times in total.

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Wed May 22, 2019 7:23 pm

anightin wrote:
Wed May 22, 2019 7:12 pm
Any clues of what debug steps I need to follow?
Can I just check some of the basics....

Which software release did you put on the Pi's SD Card?

Can you post a photo of the following two pages:
- the top level menu (just press the left button)
- the Info / Firmware Version page

Dave

User avatar
anightin
Posts: 137
Joined: Thu Aug 23, 2018 1:03 pm
Location: Cambridge UK
Contact:

Re: Atom Video to HDMI Adapter

Post by anightin » Wed May 22, 2019 7:29 pm

git version: 20181216 c854ecb
build version: RGBtoHDMI_20181216_c854ecb

.. just about to re-assemble and get a picture

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Wed May 22, 2019 7:34 pm

anightin wrote:
Wed May 22, 2019 7:29 pm
git version: 20181216 c854ecb
build version: RGBtoHDMI_20181216_c854ecb

.. just about to re-assemble and get a picture
That's the wrong version.

You need to be using the "Atom Video to HDMI Testers Release #1"
https://github.com/hoglet67/RGBtoHDMI/releases

Are you following the steps on the wiki page?
https://github.com/hoglet67/RGBtoHDMI/w ... ure-the-pi

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Wed May 22, 2019 7:34 pm

anightin wrote:
Wed May 22, 2019 7:29 pm
git version: 20181216 c854ecb
build version: RGBtoHDMI_20181216_c854ecb

.. just about to re-assemble and get a picture
That's the wrong version.

You need to be using the "Atom Video to HDMI Testers Release #1"
https://github.com/hoglet67/RGBtoHDMI/releases

Are you following the steps on the wiki page?
https://github.com/hoglet67/RGBtoHDMI/w ... ure-the-pi

User avatar
anightin
Posts: 137
Joined: Thu Aug 23, 2018 1:03 pm
Location: Cambridge UK
Contact:

Re: Atom Video to HDMI Adapter

Post by anightin » Wed May 22, 2019 7:45 pm

Oops, my apologies :oops:

All working now, thanks Dave =D>
54B76B27-8A9E-409A-A2B8-E8A552363DD0.jpeg
Last edited by anightin on Wed May 22, 2019 7:49 pm, edited 1 time in total.

User avatar
hoglet
Posts: 8186
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol
Contact:

Re: Atom Video to HDMI Adapter

Post by hoglet » Wed May 22, 2019 7:46 pm

anightin wrote:
Wed May 22, 2019 7:45 pm
All working now, thanks Dave =D>
Excellent stuff....

User avatar
anightin
Posts: 137
Joined: Thu Aug 23, 2018 1:03 pm
Location: Cambridge UK
Contact:

Re: Atom Video to HDMI Adapter

Post by anightin » Wed May 22, 2019 8:19 pm

I guess that wraps it up for tonight then :o . Now to play frogger for a bit in colour :wink: .
IMG_3523.jpeg
Have a great evening Dave and all.

Best wishes

Andy

User avatar
IanB
Posts: 376
Joined: Sun Sep 04, 2011 7:28 pm
Location: South Wales
Contact:

Re: Atom Video to HDMI Adapter

Post by IanB » Thu May 23, 2019 12:22 pm

anightin wrote:
Wed May 22, 2019 8:19 pm
Now to play frogger for a bit in colour
You have quite a few Atom palettes to choose from although the default one is the most practical, they are:

Atom MKI Card
Atom MKI Card Full
Atom MKII Card
Atom MKII Card Plus
Atom MKII Card Full
Atom 6847 Emulators

The MK1 versions try to emulate the original Acorn colour card for the Atom which just PAL encoded the YUV signals coming out of the 6847 chip resulting in a PAL 60Hz signal which wasn't very compatible with TVs of the time.
The reds, greens and blues aren't pure like the BBC's TTL RGB signals due to the way the 6847 creates the YUV signals and also the saturation of the colours has been reduced so that if you set the output to monochrome they are converted back to 4 level luminance exactly like a monochrome Atom.
The difference between Atom MKI Card & Atom MKI Card Full is that the Full version includes the low level green and orange backgrounds on text and the other one replaces them with black.

The MKII versions try to emulate the second Acorn colour card which first converted the YUV signals to TTL RGB and then PAL coded the result. It also converted the output to 50Hz for better TV compatibility.
Atom MKII Card has exactly the same 8 TTL colours as the original MKII card with oranges converted to red and the low level green and orange backgrounds on text converted to black.
Atom MKII Card Plus has the Oranges added back in (this is the default).
Atom MKII Card Full has the low level green and orange backgrounds on text added back as well.
If you set the output to monochrome with any of the MKII palettes, you will get 8+ different luminance levels so it's not an exact representation of a monochrome Atom. (Unless you were viewing the output of the MKII colour card on a black and white tv)

Atom 6847 Emulators is a palette used by some emulators. This is similar to the Atom MKI Card Full above but leaves the colours over saturated so they don't produce a correct monochrome conversion.

Post Reply