STICKY: Using a Gert VGA 666 adapter - [HOWTO]


145 posts   Page 6 of 6   1, 2, 3, 4, 5, 6
by james-at-lo-tech » Thu Feb 16, 2017 8:56 pm
No, the resistor values simply govern the DAC accuracy and any resultant non linearities at bit place boundaries, which show up as dark or light lines across smooth colour shading gradients. The values should really be slightly lower than specified, especially at the MSB end, due to the output impedance of the RPi.

The PiSupply board appears to be run directly from the open source gerbers. There is even a note on the product page that the EMC aspects have had no consideration.
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by mikechi2 » Thu Mar 09, 2017 3:17 am
Hi Guys - sorry to hijack the thread, but I thought I'd post this, which might be interesting for everyone:

https://retropie.org.uk/forum/topic/852 ... -video-hat

Image

It's a 24-bit DPI->RGB->Component Video transcoder. Same idea as gert's vga666 but adds buffering, voltage regulation and an analog circuit to convert RGB to YPbPr.

Currently it uses the same binary weighted architecture although IMO, a R2R would work better. It's hard to find 8 decades of resistor values, at the correct precision. R2R only needs to match with each other. I believe the output impedance should just be a constant 'R', no?

Everything works great except for some background noise on some TVs.

PS - Any chance of massaging the DPI sync timing to output interlaced video? Asking too much? :)
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by RealGrupa » Wed Mar 29, 2017 8:22 am
Hello,

Need help, I was following the steps, and after editing the confing file and after step 3. when I reboot, the rasp is going to recovery mode..

Any ideas?

Ty
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by procount » Wed Mar 29, 2017 12:56 pm
@RealGrupa - Are you trying to use the VGA666 with NOOBS? If so, the DPI will be forcing NOOBS into safe mode.
Try adding 'disablesafemode' to recovery.cmdline. (see here)
IIRC I had to make some other modifications in PINN to make it compatible with DPI mode, so if NOOBS still doesn't work with the above modification, just replace NOOBS with PINN and it should work (with the above mod).

DO NOT just blindly copy recovery.cmdline from PINN onto your SDcard
, as the default is to WIPE the SD card due to the presence of the 'runinstaller' option, so make sure this is removed. You might want to review the other options available like ssh, vncshare, alt_image_source etc to enable the additional features and OSes to install. It works almost identically to NOOBS
PINN - NOOBS with the extras... https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=142574
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by amichel72 » Tue May 09, 2017 2:28 pm
Hallo to everybody and thank u for your time.
I have installed my VGA666 and it runs correctly. I already want to set-up my joystick on free gpio's on board.
I did the correct procedure (drivers and configurations) but when i have to set the GPIO's (from 22 to 27) with this command:
"sudo modprobe mk_arcade_joystick_rpi map=5 gpio=22,23,24,25,26,27,-1,-1,-1,-1,-1,-1" the monitor shutdown;
"sudo modprobe mk_arcade_joystick_rpi map=5 gpio=22,23,24,25,26,27" the monitor shutdown;
"sudo modprobe mk_arcade_joystick_rpi map=5" the monitor shutdown;
"sudo modprobe mk_arcade_joystick_rpi map=1" joystick and buttons works well, but my monitor looses colors
So the question is: can I setup my josystick and the VGA monitor in the GPIO's both?
How can I do to solve this problem?
Thank u again.
Andrea
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by BMS Doug » Tue May 09, 2017 11:26 pm
The gert vga666 doesnt leave many spare gpio pins, certainly not the 6 you need for your joystick.

I would suggest a usb joystick or a hdmi to vga adaptor.
Doug.
Building Management Systems Engineer.
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by Gert van Loo » Wed May 10, 2017 7:32 am
You can reduce the number of colours which will then free up GPIO pins.
e.g. make it a VGA 555. That gives 3 more GPIO pins but reduces the number of available colours to 2^15 = 32767 instead of 2^18 = 262144.
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by petra2201 » Thu May 11, 2017 3:36 pm
I have a raspberry pi 2 and am using the May 2016 Jesse version or raspbian. I have two gert vga 666's one I hand soldered and one I bought from a vendor. When I follow this how to I get no output on the vga. Is there anything I can check (error logs, etc) to begin to troubleshoot this? I have two pi's with the exact same setup and they work fine on hdmi but I get nothing on vga under any resolution. Here's the steps I took to try and get video.
Copied the steps exactly as I saw form the 1st post.
I tried using the manual from the gert and copying over blob.bin into boot.

So any suggestions where I can look to troubleshoot?
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by FTrevorGowen » Thu May 11, 2017 5:40 pm
petra2201 wrote:I have a raspberry pi 2 and am using the May 2016 Jesse version or raspbian. I have two gert vga 666's one I hand soldered and one I bought from a vendor. When I follow this how to I get no output on the vga. Is there anything I can check (error logs, etc) to begin to troubleshoot this? I have two pi's with the exact same setup and they work fine on hdmi but I get nothing on vga under any resolution. Here's the steps I took to try and get video.
Copied the steps exactly as I saw form the 1st post.
I tried using the manual from the gert and copying over blob.bin into boot.
So any suggestions where I can look to troubleshoot?

W.r.t. "copying over blob.bin into boot." : IIRC, that method's "out of date"** and "all" that's needed are appropriate entries in config.txt - check what you did with my notes here: http://www.cpmspectrepi.uk/raspberry_pi ... apter.html
Trev.
** for Raspbian Jessie a dtoverlay was created.
Usually running Raspbian Jessie on up to 13 Pi's (an A, B1, 2xB2, 2xB+, A+, P2B, 3xP0, P3B, P0W). See: https://www.cpmspectrepi.uk/raspberry_pi/raspiidx.htm
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by petra2201 » Thu May 11, 2017 8:27 pm
I was using an older version of raspbian, I saw that you're using pixel so I switched to that and it's working. Thanks!
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by flasan » Mon May 15, 2017 12:22 pm
This setting worked here on my raspberry pi 3 b. Thank you very much!

Can use both VGA666 and HDMI simultaneously?
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by petra2201 » Mon May 15, 2017 5:00 pm
Someone posted a config a few pages back that would do that but it doesn't work like you'd think. You can have two outputs but as far as I can see you have to use shell and specify which display your program should run on.
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by amichel72 » Sat May 20, 2017 12:21 pm
News about how to use gert VGA and joystick controls on GPIO's both?
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by Gert van Loo » Sat May 20, 2017 7:29 pm
amichel72 wrote:News about how to use gert VGA and joystick controls on GPIO's both?


Not without some type of I/O expander, there are not enough pins.
Some suggestions have been made but you seem to keep asking for the impossible.
You can't get en elephant into a Volkswagen, it has been tried :-)
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by amichel72 » Sun May 21, 2017 12:34 pm
HAHA nice answer!
I put in the GPIO'S the expander "RPi-VGA-Shield3 you can see in the attached image.
It has on board GPIO pins from 22 to 27, ground and 3,3 + 5 V.
So my poupose is to use those free pins.
Yesterday i have tried again, with good results just on the following pins: 22,23,26,27 (My joystick works, not the buttons).
And...
Do you know how to sit four elephants in a mini?

Two front and two behind :D
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by Burngate » Mon May 22, 2017 9:07 am
And how do you get four giraffes in a mini?

Take out the elephants.
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by flasan » Wed May 31, 2017 10:06 pm
tvjon wrote:If anyone using Gert's adapter would like to use both hdmi & vga simultaneously, I've found this to work ok:

My relevant settings in

config.sys

enable_dpi_lcd=1
display_default_lcd=0


Open terminal (visible screen being hdmi, as display default for DPI is set to 0 above)

pi@pi2 ~ $ omxplayer --display 4 pi2-clkpwm.webm.mp4

Obviously choose your own video file.

Below is terminal output for the poor quality attached jpeg.

pi@pi2 ~ $ omxplayer --display 4 pi2-clkpwm.webm.mp4

Invalid framerate 1000, using forced 25fps and just trust timestamps
Video codec omx-vp8 width 1280 height 800 profile -99 fps 25.000000
Subtitle count: 0, state: off, index: 1, delay: 0
V:PortSettingsChanged: 1280x800@1000.00 interlace:0 deinterlace:0 anaglyph:0 par:1.00 layer:0
V:PortSettingsChanged: 1280x800@1000.00 interlace:0 deinterlace:0 anaglyph:0 par:1.00 display:4 layer:0
have a nice day

I actually have the DPI setting for 1024*768, but have since tried another old vga monitor, capable of 1280*1024 & it seems happy to play high res' files.

VGA666 is currently displaying a BBC HD recording & cpu usage hasn't risen beyond 10%.


666dualmonitors.jpg


Hello,
I tried this setup without success. Would you help me?
Is it possible to run a browser on the second screen?
thank you
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by magwe » Fri Jun 02, 2017 12:58 pm
Hi,

So I would like to use the Gert666 to output to my TV over SCART.

As far as I understand it I can't just splice a VGA cable with a SCART cable and expect that to work unless I combine the VGA HSYNC+VSYNC pins into a common CSYNC using a xor gate, right ?

Is possible to simply modify the DPI driver to optionally do this for me so that a simple cable splice would work?

Where would I find the DPI driver?

Thanks
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by Torni69 » Sat Jun 17, 2017 11:32 am
Hi,
i also bought a VGA666-Adapter, assuming, that using my HDMI-Monitor and my Beamer (using Libreelec) at the same time is not a problem.

But, it seems like it is - have to deal with that, until some update changes that :cry:

Still I have a "technical" questions about that:

If the VGA666 is activated and the HDMI switches off, does that mean, that the COMPLETE HDMI-Signal is cut off, or is it just about the Video-Signal and I can still use HDMI Sound?

If so, did anybody write (or is willing to) a script, that i could use in Libreelec (maybe in the shutdown-menu?), wich changes the "display_default_lcd" entry in the config.txt from 0 to 1 and vice versa and then reboots?

My "workaround" would then be, to use my Kodi-HTPC either with the HDMI Monitor (at Daytime) OR the Beamer by just "switching" it with the script, but as i am going to buy a HDMI-to-6.1-Audio-Interface, i would still need to have sound on the HDMI.

Hope, anybody will understand my request, wich might sound a bit weird, though english is not my native language and I can be calles a "Noob" with o´no doubt :mrgreen: . Nevertheless I am thankful for any helping answer ;)

Regards, Juergen
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by Torni69 » Wed Jun 28, 2017 2:18 pm
Hm, no reply until now :(

So, with the help of Go...oogle and a bit of luck I managed to write my own script, that switches between 2 different "config.txt" - one with VGA666 disabled, one with it enabled -, I assume it's pretty complicated :?

Code: Select all
#!/bin/bash
mount -o remount,rw /flash
mv /flash/config.txt /flash/config-old.txt
mv /flash/config.old /flash/config.txt
mv /flash/config-old.txt /flash/config.old
reboot


I also found a little app for my android, called "SSH Button", wich logs into my PI using SSH and starts the script with only the press of a button (also available as a widget).

It is not the smartest solution I can imagine, and I have still no idea, if HDMI-Audio is still working when VGA666 is active, but for now it works and I can switch from HDMI-Monitor to Beamer and back with a minimum of effort....

Just, if anybody is looking for a solution and likes my idea ;)
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