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HDMI->VGA and Raspberry Pi.

by Robert Lipe on Thu Jan 24, 2013 12:26 am

First, a word of thanks for being awesome for all these years. I've been a fan for years, but only this week became a customer. I needed to enter the Raspberry Pi world for a low number of units. I decided to do the totally easy thing and just click "buy from AdaFruit" for everything, hoping to benefit from your integration expertise. (For this project, I'd rather spend tens of dollars on a power supply or SD card than tens of hours debugging a problem by a crappy phone adapter.)

Most of the equipment in my life is a generation ahead or behind from HDMI. It's not like RPI has a Thunderbolt or Dual DVI link and everything I have older than that goes no lower than VGA. So I decided to throw product 1151 in my cart and hope to drive an old VGA monitor.

I can tell the Pi is booting. I see Ethernet activity links on boot. I see it get a DHCP grant from my DHCP server. It responds to pings. The LED pattern is consistent for an older Linux-y system boot. But I get ZERO HDMI action. I can't try the cable in anything else, but in light of viewtopic.php?f=50&t=36263 I'm wondering if this cable is actually compatible with Pi. I know this forum isn't for RPI, and I can't see that D1 is visibly flamed out, but the tutorials all need video to edit the configs (doink!) and shorting GPIO1 low doesn't result in video. So I can't tell if my RPI is bad, the cable/converter is bad, or if I need to edit configs that I can't edit without seeing video.

Any suggestions on how to break this tie? (That don't involve something absurd like buying another monitor...)

Thanx
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Re: HDMI->VGA and Raspberry Pi.

by adafruit on Thu Jan 24, 2013 11:29 am

We have tested this product with the Pi:

We tried this out with a Raspberry Pi and an old VGA monitor we had and found the display output to be very crisp and vivid. For use with a Raspberry Pi we suggest editing config.txt to set "hdmi_safe=1" output for best results (otherwise, the Pi may not 'recognize' the HDMI display and revert to composite output)


You need to put the SD card in your computer and edit config.txt to set HDMI_SAFE mode. did you do that?
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Re: HDMI->VGA and Raspberry Pi.

by Wintersdark on Fri Feb 01, 2013 2:00 am

Ok, I was able to get this going, but it took some doing.

I'm running RaspBMC (xbmc setup for the raspberry pi, built on debian iirc).

hdmi_safe=1 in the config.txt file allowed the monitor plugged into the HDMI>VGA adapter to work during the setup (text based) but after the setup was complete, when the Pi rebooted I lost video.

The Pi would clearly be running, and I was able to SSH in (user: pi password: raspberry) and the shell worked fine. Clearly, then, the pi was working. So, a problem with display!

What worked for me:

Which values are valid for my monitor?

Your HDMI monitor may support only a limited set of formats. To find out which formats are supported, use the following method.
Set the output format to VGA 60Hz (hdmi_group=1 hdmi_mode=1) and boot up the Raspberry Pi
Enter the following command to give a list of CEA supported modes
/opt/vc/bin/tvservice -m CEA
Enter the following command to give a list of DMT supported modes
/opt/vc/bin/tvservice -m DMT
Enter the following command to show your current state
/opt/vc/bin/tvservice -s
from: http://elinux.org/RPi_config.txt


Turns out, hdmi_group=1 and hdmi_mode=1 would allow the Pi to boot up graphically and work fine, but I am currently stuck at a horrendous 640x480. The above commands which show supported modes show that ONLY that mode will work, and my tests have lead to the same result. Other group/mode selections lead to a blank screen.

If there's any way to get other modes working, I'd love to hear it. Being stuck at that resolution makes this largely useless to me, as I was hoping to drive my old LCD monitor (it's dvi input broke years back, but vga works fine - and it takes all manner of resolutions from my desktop over VGA with no issues) at it's native 1680x1050, or at least a standard 720p res.

It's a media center Pi, after all, nobody wants to watch movies at 640x480.
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Re: HDMI->VGA and Raspberry Pi.

by Wintersdark on Fri Feb 01, 2013 12:48 pm

Has anyone been able to get this adapter running at other resolutions?
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Re: HDMI->VGA and Raspberry Pi.

by Wintersdark on Sat Feb 02, 2013 2:54 pm

adafruit wrote:We have tested this product with the Pi:

We tried this out with a Raspberry Pi and an old VGA monitor we had and found the display output to be very crisp and vivid. For use with a Raspberry Pi we suggest editing config.txt to set "hdmi_safe=1" output for best results (otherwise, the Pi may not 'recognize' the HDMI display and revert to composite output)


You need to put the SD card in your computer and edit config.txt to set HDMI_SAFE mode. did you do that?


To clarify, did you test this product in a variety of graphics modes? Maybe something's just wrong with mine, or it's typical user error somewhere.

HDMI_SAFE only seems to work for text. As I showed above, I was only able to get it to allow VGA mode - 640x480, or HDMI_MODE=1 and HDMI_GROUP=1. Blank screen with any other graphic mode.

I'm only harping on this, because if the above is the case (limited to 640x480 graphics) then you absolutely should put this in the technical details/specs for this product. It's pretty misleading otherwise.
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Re: HDMI->VGA and Raspberry Pi.

by adafruit on Wed Feb 06, 2013 11:37 pm

We booted it with occidentalis/rasbian, don't recall the precise resolution we got but it was definately > 640x480 & iirc all we changed was hdmi_safe. but cant recall if we checked all the graphics modes.

can you try a fresh raspbian install just for debugging check?
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Re: HDMI->VGA and Raspberry Pi.

by 3boysdad on Sun Mar 10, 2013 4:29 pm

seems that the RaspBMC works fine with this device and I too had a similar problem the blank screen over HDMI using the most recent version of Wheezy. wonder what the problem is exactly...
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Re: HDMI->VGA and Raspberry Pi.

by radiojack on Tue Mar 19, 2013 7:37 am

Same issue here - using the Adafruit HDMI to VGA adapter with a Viewsonics VGA monitor. I tried all the switches in CONFIG.TXT that have been suggested in forum posts. The monitor comes out of sleep mode but displays no text. No joy with Raspbian, Raspbmc. HDMI works find when the Pi is connected to an HDTV.
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