Combined VGA / Tube interface board for Atom

[hoglet]

Hi all,

I've now got one of Ken's latest Combo VGA/Tube boards built up and installed:

So far I haved tested:
- the Pico AtomVGA with VGA output
- the Pico AtomVGA with RGBtoHDMI output
- the internal Tube (a built-in PiTubeDirect level shifter)
- the external Tube (a Matchbox in this case)
- the latest AtomVGA.uf2 with genlock

The left screen is the VGA output, the right screen is the RGBtoHDMI output:

Everything is working perfectly so far.

Here's a couple of screen grabs from PiTubeDirect:

Well done Ken, and to every that's worked on AtomVGA (Chris and Phill) and RGBtoHDMI (Ian).

Dave

[hoglet]

Here's the latest atomvga.uf2 with genlock:

4638fbb1.zip

(32.13 KiB) Downloaded 27 times

Here's the latest COLTEST test program:

COLTEST.zip

(778 Bytes) Downloaded 21 times

COLTEST accepts the following keys:
- 0: Genlock mode 0 (Genlock disabled)
- 1: Genlock mode 1 (Genlock by varying the pixel clock)
- 2: Genlock mode 2 (Genlock by varying the horizontal line length
- 3: Genlock mode 3 (Genlock by varying the number of lines before the vsync pulse)
- 4: Genlock mode 4 (Genlock by varying the number of lines in the vsync pulse)
- 5: Genlock mode 5 (Genlock by varying the number of lines after the vsync pulse)

It's been a pleasure to help out with this project.

Dave

[KenLowe]

The Atom Technical Manual component layout shows the 'pin1' dot for PL7 at 'a1' with it in what seems to be the conventional (ABBA) orientation.

That's a good point of reference. If using the female DIN41612 B connector, it would be orientated like this:



It does of course mean that 5v is on b1, and gnd is on b32, which is contrary to the info shown in this post:

viewtopic.php?p=313419#p313419

...although, I'm not sure what the source of that information is.

If we therefore accept the ABBA convention, and the fact that power is on the b row of pins, then anyone designing a board that plugs into the PL7 connector using the male DIN41612 Q connector needs to follow the pinout convention below. I just think this looks so wrong, but general consensus is that this is how it should be:



This is opposite to what I did for my PicoVGA board, where I had +5v on a1 and gnd on a32 (ie connector rotated by 180 degrees). I'll update my Kicad design to reflect the pinout above, and leave the Atom PL7 female board connector in its current orientation.

[KenLowe]

Here's the latest atomvga.uf2 with genlock:
4638fbb1.zip

Here's the latest COLTEST test program:
COLTEST.zip

COLTEST accepts the following keys:
- 0: Genlock mode 0 (Genlock disabled)
- 1: Genlock mode 1 (Genlock by varying the pixel clock)
- 2: Genlock mode 2 (Genlock by varying the horizontal line length
- 3: Genlock mode 3 (Genlock by varying the number of lines before the vsync pulse)
- 4: Genlock mode 4 (Genlock by varying the number of lines in the vsync pulse)
- 5: Genlock mode 5 (Genlock by varying the number of lines after the vsync pulse)

It's been a pleasure to help out with this project.

Dave

Ok, modes 2 & 3 both give me a nice stable picture on my Lenovo monitor. The pixel line colour issue I was seeing on the Manic Miner loader screen has also disappeared on both of these modes. The two levels of orange is a nice add.

[KenLowe]

I'm getting myself a bit confused here. I'm trying to get the RGB side of my PicoVGA board working with my RGBtoHDMI board, but it's not working correctly.

On the RGBtoHDMI side, I'm using an Issue 3 RGBtoHD 6/8 Bit board. I've flashed the CPLD with the latest Beta56 firmware, and I've connected the RGBtoHDMI board to my PicoVGA board with a 2 x 6 way IDC ribbon.

On the PicoVGA side, I've flashed the firmware from the most recent 4638fbb1.zip. I've connected the VSYNC signal from PL4 to the PicoVGA board, and I've tried all the different genlock options from the COLTEST utility but I get a Sync Not Detected for all genlock modes (including disabled).

From the RGBtoHDMI menu, I've tried all the available profiles (I couldn't find an Atom VGA profile, so I've left it at Atom TTL), but I get a Sync Not Detected for all profiles. The Atom picture is usually repeated 4 times on the screen, and the image scrolls up or down the screen.

The image is stable on the VGA side of the board.

What am I doing wrong?

[hoglet]

From the RGBtoHDMI menu, I've tried all the available profiles (I couldn't find an Atom VGA profile, so I've left it at Atom TTL), but I get a Sync Not Detected for all profiles. The Atom picture is usually repeated 4 times on the screen, and the image scrolls up or down the screen.

Something is not quite right then....

Can you go to the Info/System Summary menu and tell me what Kernel Version and CPLD Version are being reported?

(Or do a screen shot by pressing buttons 2 and 3 at the same time)

Make sure to use the new Select Profile menu (right at the bottom), then select Acorn, then you should see Atom VGA. It might be called (RGB) Atom VGA if you don't have the right CPLD programmed. This menu should handle reprogramming the CPLD automatically for you, if that is needed.

Dave

[KenLowe]

Ah, I was using the wrong CPLD version. I had wrongly selected the BBC version. I've switched it to the RGB version, found the Atom VGA profile and it's now working. What a great picture! I thought the VGA picture was good, this is an order of magnitude better. It is so crisp!

I'm trying to get my second Atom (my original Atom, number 1) fully up and running with a second AtoMMC / Econet board, with its own SD card. I installed the latest 12.03 ASA, but couldn't get the OZMOO games to run. I then remembered that I still needed to copy over the latest OSWRCH80 driver. That fixed that issue!

Next issue was that I couldn't get genlock. Turns out that the VSYNC wire had dropped off PL4! Also now fixed.

All good now .

I'm absolutely delighted with how it's all worked out on both my Atoms! Thank you again for all your support.

[hoglet]

All good now .

I'm absolutely delighted with how it's all worked out on both my Atoms! Thank you again for all your support.

I'm pleased it was something simple.

So what's next on the Atoms????

Dave

[KenLowe]

So what's next on the Atoms????

Haha, good question! @oss003 suggested I need to get AtomSID in one of my other threads. That seems to be the only thing missing. It's not something I've looked into at all... yet!

[KenLowe]

Right, that's this project pushed to github:

https://github.com/kgl2001/Atom_VGA_Tube_Combo

Let me know if there are any issues.

[dreamerxb]

Because I find this a great project I build one for my self but I can't get it working, can someone help me to get in the right direction ?

Here are some pictures I took:

When pressing break I get this picture

[KenLowe]

Have you bypassed IC4 (8304)? See point 4 from this post. I can't see clearly from the photo, but it looks like there's still an IC in that socket.

[dreamerxb]

Thanks, I didn't bypass ic4 but know I have. I don't get the screen with the red bars anymore only the picture with pico atom vga.

[hoglet]

Thanks, I didn't bypass ic4 but know I have. I don't get the screen with the red bars anymore only the picture with pico atom vga.

Have you tried pressing BREAK a couple of times?

Does Control-G then make a beeping sound?

Dave

[hoglet]

Also, for now I would disconnect both flying leads connecting to PL4, these are optional.

If you want to genlock the VGA output to the 6847 frame sync, then you need a single flying lead connecting the lower pin on the header (marked VSYNC) to PL4 pin 5 (FS)

[KenLowe]

Also, do you get anything from the UHF output, or the PL4 connector? Both with the Combo VGA / Tube interface plugged in and removed?

[dreamerxb]

Thanks, I didn't bypass ic4 but know I have. I don't get the screen with the red bars anymore only the picture with pico atom vga.

Have you tried pressing BREAK a couple of times?

Does Control-G then make a beeping sound?

Dave

Thanks Dave and KenLowe

Sorry for the late response, I was on a trip to Berlin. I tried pressing a couple of times the break key with no result. Control-G creates no sound. If i remove the combined VGA and let the bypass on IC4 in it and connect the RGBtoHDMI on PL4 the atom it looks like it is stuck. when I remove the bypass the atom works fine. When I put the combined VGA back with the bridge and connect the RGBtoHDMI on PL4 I can see when pressing serveral times on the break key that, through the HDMI, the screen with blocks is changing by every break key press. So I a suppose the cpu is responding and is not stuck.

[KenLowe]

Are you sure you've got the IC4 bypassed correctly? In particular, watch out for the one pin offset between the pins on the left and the pins on the right!

8304A Bypass

8304A Bypass

[dreamerxb]

Thanks Ken

You are right, one or more pins didn't make good contact but now day do.

The result is now that the atom is not stuck any more but has a weird pattern of characters

[oss003]

Looks like D2 of the video is always '1'
Please check the bridge between pin 3 and 17 of the 8304.

Greetings
Kees

[KenLowe]

The result is now that the atom is not stuck any more but has a weird pattern of characters

Is that with the AtomVGA board plugged in, or removed? If the AtomVGA board is removed, what happens if you also remove the IC4 bypass? As @oss003 suggests, it's definitely worth checking for bridges around IC4.

[dreamerxb]

The result is now that the atom is not stuck any more but has a weird pattern of characters

Is that with the AtomVGA board plugged in, or removed? If the AtomVGA board is removed, what happens if you also remove the IC4 bypass? As @oss003 suggests, it's definitely worth checking for bridges around IC4.

It is plugged in. When I remove the bypass and leave the VGA board in it the atom has a blank screen but is running. ( it beeps by pressing ctrl-g )
I wil check if there is a bridge around IC4

Thanks

[hoglet]

The result is now that the atom is not stuck any more but has a weird pattern of characters

Is the monitor in these photos connected to the Combo/VGA board or to RGBtoHDMI/PL4?

[dreamerxb]

The result is now that the atom is not stuck any more but has a weird pattern of characters

Is the monitor in these photos connected to the Combo/VGA board or to RGBtoHDMI/PL4?

The combo/VGA board

[KenLowe]

Is the monitor in these photos connected to the Combo/VGA board or to RGBtoHDMI/PL4?

The combo/VGA board

Ok, so can you confirm that the display is ok on the RGBtoHDMI/PL4 connector?

[hoglet]

The combo/VGA board

OK, then I think you probably have a break somewhere in the D2 line.

Note: D2 is actually the end jumper on IC4 (that connects pins 1/19)

Try measuring the resistance from pin 31 of the 6502 (D2) to pin 5 of U5 on the ComboVGA board. This should be 33 ohms.

Dave

[dreamerxb]

Thanks to all but I think that my board has a defect, it shows now nothing anymore . The atom works, luckily without any problems on the RGBtoHDMI.
I used components from alliexpress so I think I have to troubleshoot first if there is a component broken.
As soon I know something I wil report it back.

Many thinks so far. We were, I think, close to a solution.

[KenLowe]

Thanks to all but I think that my board has a defect, it shows now nothing anymore . The atom works, luckily without any problems on the RGBtoHDMI.
I used components from alliexpress so I think I have to troubleshoot first if there is a component broken.
As soon I know something I wil report it back.

Many thinks so far. We were, I think, close to a solution.

I think you're pretty close to getting this working. I don't think there's anything too fundamentally wrong. As has been said by others, it's only D2 that's causing intermittent corruption on the screen. Areas of focus would be the IC4 jumper (between pins 1 & 19), the 3rd resistor on resistor bank RN1, and pin 5 on U5.

D2 routing on AtomVGA

[dreamerxb]

Thanks a lot to you all. The Atom with Combined VGA/Tube Interface board is working. It was a bad solder connection on R12 which causes no picture and as you guys already told, the D2 trace. The resistor array had a bad connection as well as U5. I reflow those components and it worked
I am verry happy it works, thanks for all the support.

By the way, I use also the Atomsid which is with the VGA board not playing well anymore, do I have to change some addresses ?

[KenLowe]

Nice. Well done .

You might want to try the RGB output from the VGA board (CN4); particularly if you already have a standard RGBtoHDMI adaptor. The picture quality from that is super impressive, and you can even get screen captures from the RGBtoHDMI adaptor. That's not been implemented on the VGA interface / Pico module; even though there's a capture button on the VGA connector board.

I'm not sure about AtomSID. I don't have one of those.