sdmeijer
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[resolved] Gert's VGA66 - two issues

Thu Sep 25, 2014 6:13 pm

Hi Gert,

I hope you can help me. I've made (on breadboard) a VGA666.
But I have two problems:
1. White is displayed as yellow.
2. I do get a screen during booting and when the GUI loads I can see the RPi wallpaper for about 3 seconds and then the screen goes blank (but it gets a signal, because it doesn't go into sleep mode).

How can I solve these?

Best regards,

Sjoerd Dirk Meijer
the Netherlands
Last edited by sdmeijer on Thu Sep 25, 2014 7:22 pm, edited 2 times in total.

sdmeijer
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Joined: Thu Jun 21, 2012 6:13 pm

Re: Gert's VGA66 - two issues

Thu Sep 25, 2014 6:16 pm

I've asked this first in a PM to Gert (and after that made this post).

My first problem is probably due to one of my green bits not working. I'll look into it.

Hope I get a solution for the second problem soon ;-)

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Gert van Loo
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Re: Gert's VGA66 - two issues

Thu Sep 25, 2014 6:22 pm

1. White is displayed as yellow.
My guess would be that one of your bits (green bit?) is not working.
2. Screen disappears.
That is a weird one. Can't think immediate of a reason. (somebody else??)
Not going to sleep indicates that the syncs (hor./vert.) are still present.

sdmeijer
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Re: Gert's VGA66 - two issues

Thu Sep 25, 2014 6:26 pm

Solution for problem no. 1:
I've misplaced the jumper wire for the blue bit one hole on the breadboard ;-) So that was an easy one ;-)

sdmeijer
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Re: Gert's VGA66 - two issues

Thu Sep 25, 2014 6:59 pm

I think I also found the reason for problem no. 2:

I'm using a 1.2A power supply and I've set the overclocking to "turbo" mode.
After disabling "turbo" everything works fine.
I'm now testing it:
Medium (2 overvolt): working
High (6 overvolt): working
Turbo (6 overvolt): NOT working

I don't have a 2A power supply. I'll try Turbo mode when I can get my hands on it.
So I think it has to do with the power supply.

P.S. I'm using 330 Ohm resistors (couldn't find anything lower in my collection, besides the 80, 100 and 120 I bought today) for HSync and VSync without any problems!

sdmeijer
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Re: [resolved] Gert's VGA66 - two issues

Thu Sep 25, 2014 7:21 pm

I've posted a photo of my setup on Twitter:
http://pic.twitter.com/BtBwkX9qI7

Image

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DougieLawson
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Re: [resolved] Gert's VGA66 - two issues

Thu Sep 25, 2014 8:02 pm

You need a better power supply. You've got the little B+ coloured square in the top corner (above and to the right of the Minecraft window).

That wiring loom also makes my desk look tidy.
Note: Having anything humorous in your signature is completely banned on this forum. Wear a tin-foil hat and you'll get a ban.

Any DMs sent on Twitter will be answered next month.

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sdmeijer
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Re: [resolved] Gert's VGA66 - two issues

Fri Sep 26, 2014 5:24 am

DougieLawson wrote:You need a better power supply. You've got the little B+ coloured square in the top corner (above and to the right of the Minecraft window).
Ah, thanks. I was wondering what that coloured square was.
DougieLawson wrote:That wiring loom also makes my desk look tidy.
It's a quickly made breadboarded prototype, without any intentions to make it tidy ;-)
My next version will be, because I want to stack it on the GPIO pins.

arm2
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Re: [resolved] Gert's VGA66 - two issues

Thu Oct 02, 2014 10:54 am

DougieLawson wrote:You need a better power supply. You've got the little B+ coloured square in the top corner (above and to the right of the Minecraft window).
Hi Dougie Can you explain more please?
I've tried searching the forums but obviously not used the right search terms.

EDIT: More searching found the answer at:http://www.raspberrypi.org/forums/viewt ... 29&t=82373

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DougieLawson
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Re: [resolved] Gert's VGA66 - two issues

Thu Oct 02, 2014 11:08 am

arm2 wrote:
DougieLawson wrote:You need a better power supply. You've got the little B+ coloured square in the top corner (above and to the right of the Minecraft window).
Hi Dougie Can you explain more please?
The model B would just give up the ghost if the voltage browned out below about 4V7. Brownouts could cause SDCard corruption.

With the model B+ the foundation did lots of work to improve the power supply, to make the USB power more stable (and rated at 1A2 if needed and if the power supply can handle it). They also added some magic in the GPU processing code to give a visual indication that the power budget was on the limit (with the funky square on the video signal). It will also turn the power LED off.
Note: Having anything humorous in your signature is completely banned on this forum. Wear a tin-foil hat and you'll get a ban.

Any DMs sent on Twitter will be answered next month.

This is a doctor free zone.

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