milhouse
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Mon May 28, 2012 9:02 am

rsbrowndog wrote: Today I decided to try out OpenELEC and kept having problems with the screen on my monitor blanking out for a second or so and then coming back. Very annoying. I tried switching to a normal HDMI cable and the problem went away, so I concluded that it must be this cable drawing power from my Pi.
This blinking (HDMI handshake issue) seems to be a common problem with OpenELEC (maybe XBMC in general) and should hopefully be fixed with a future firmware update - I get it from time to time with an LG HDMI monitor while playing 720p/1080p content, and I'm using a 2A/5V HP Touchpad PSU so I'd be surprised if power is the cause, though not ruling it out.

rsbrowndog
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Mon May 28, 2012 5:28 pm

milhouse wrote:This blinking (HDMI handshake issue) seems to be a common problem with OpenELEC (maybe XBMC in general) and should hopefully be fixed with a future firmware update - I get it from time to time with an LG HDMI monitor while playing 720p/1080p content, and I'm using a 2A/5V HP Touchpad PSU so I'd be surprised if power is the cause, though not ruling it out.
Interesting, I hadn't heard of that. My son's Pi is having no issues with blinking and we've got that one hooked up via HDMI and have tested that with both OpenELEC and Raspbmc.

And I do wonder if HDMI handshake issues will actually come into play in my scenario, i.e. using a HDMI-to-VGA converter?

Regardless, the biggest indicator that I needed a bit of extra power for my Pi is surely that since implementing the Y-cable the issue has completely disappeared?

Like I said, not ruling it out, just saying what's working for me.

Cheers,

Ryan

asb
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Mon May 28, 2012 6:46 pm

rsbrowndog wrote: And I do wonder if HDMI handshake issues will actually come into play in my scenario, i.e. using a HDMI-to-VGA converter?

Regardless, the biggest indicator that I needed a bit of extra power for my Pi is surely that since implementing the Y-cable the issue has completely disappeared?

Like I said, not ruling it out, just saying what's working for me.
Yes, I've found I sometimes get the blanking screen also and it's definitely power issues. With my 850mA Kindle charger I get it when doing a full stress test (ethernet+usb+samurai demo). It's worse with a cheap 1A charger (blanks during boot). I've found my 2A Samsung charger solid as a rock though, even with the stress test and keyboard+usb stick connected. These devices will draw power from the Pi, this eating in to your power budget. In practice, with my peripherals and a good power supply I've found it manageable.

poing
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Mon May 28, 2012 7:39 pm

asb wrote: Yes, I've found I sometimes get the blanking screen also and it's definitely power issues. With my 850mA Kindle charger I get it when doing a full stress test (ethernet+usb+samurai demo). It's worse with a cheap 1A charger (blanks during boot). I've found my 2A Samsung charger solid as a rock though, even with the stress test and keyboard+usb stick connected. These devices will draw power from the Pi, this eating in to your power budget. In practice, with my peripherals and a good power supply I've found it manageable.
OK, but with 850mA you're already above the maximum 700mA budget. So you could slowly cook your Pi (or some specific regulator components anyway) over time.

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jbeale
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Mon May 28, 2012 7:50 pm

Just want to clarify about power supplies, the current rating tells you how much the supply can provide, not the maximum it does provide (which depends on the load at any given time). It is perfectly safe to connect a 10 A rated supply to the R-Pi as long as it is 5 V, the Pi will take only the current it needs and no more.

Now, you can try connecting power-hungry USB devices to its ports, but again there is no safety issue, it just won't work. The external 5V power the R-Pi provides to USB devices does not flow through any regulators; just the onboard fuses, which are rated to limit the total input current to 700 mA, and about 140 mA at each USB output. The fuses are actually a reason many USB peripherals do not work on the Pi directly, as they often draw more than the fuses allow (too much voltage drop across the fuse for the device to work) so you need a separate powered hub for many devices.

poing
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Mon May 28, 2012 8:12 pm

Yes, but if there are problems with 850mA using the VGA converter but not with the 2A one (discarding the cheap 1A supply) it seems the max current used with some peripherals is higher than 850 mA.

I know nothing about these fuses; they can't be damaged when continually at the tripping point?

milhouse
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Tue May 29, 2012 7:40 am

poing wrote:Yes, but if there are problems with 850mA using the VGA converter but not with the 2A one (discarding the cheap 1A supply) it seems the max current used with some peripherals is higher than 850 mA.
It doesn't make sense, but I'm not arguing if it solves your problem. :)

Odd then, that I still have problems with a 2A power supply... maybe upping the power available is pointing in the right direction but I'm not entirely convinced it's the right solution - hopefully a firmware fix will do the job (maybe dom can shed some light on what causes the "blinking" and if a firmware fix is in the offing?)

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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Tue May 29, 2012 9:10 am

poing wrote:Yes, but if there are problems with 850mA using the VGA converter but not with the 2A one (discarding the cheap 1A supply) it seems the max current used with some peripherals is higher than 850 mA.
It's entirely possible that a power supply "rated" at 850mA can't quite supply 700mA - there's several threads that state that PSU ratings are often over-specified :|

rsbrowndog
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Tue May 29, 2012 2:10 pm

AndrewS wrote:It's entirely possible that a power supply "rated" at 850mA can't quite supply 700mA - there's several threads that state that PSU ratings are often over-specified :|
Exactly! My Samsung phone charger supplies 700 ma and works far better than another charge which allegedly provides 1000 ma (but clearly doesn't!)

Not all power supplies are created equal, some are FAR better than others, which is why some lower powered ones apparently perform much better than higher rated offerings.

Cheers,

Ryan

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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Tue May 29, 2012 7:08 pm

rsbrowndog wrote:
AndrewS wrote:It's entirely possible that a power supply "rated" at 850mA can't quite supply 700mA - there's several threads that state that PSU ratings are often over-specified :|
Exactly! My Samsung phone charger supplies 700 ma and works far better than another charge which allegedly provides 1000 ma (but clearly doesn't!)

Not all power supplies are created equal, some are FAR better than others, which is why some lower powered ones apparently perform much better than higher rated offerings.

Cheers,

Ryan
(A side note: Voltage is much more of a problem than current)
{sig} Setup: Original version Raspberry Pi (B, rev1, 256MB), Dell 2001FP monitor (1600x1200), 8GB Class 4 SD Card with Raspbian and XBMC, DD-WRT wireless bridge

ren41
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu May 31, 2012 1:21 pm

I bought the Neewer cable from Amazon as well and it arrived this morning. I was initially sceptical as it appears unbranded and of pretty cheap construction - however it works a treat with my LG monitor. As yet I haven't had any issues such as the screen blanking out, so hopefully all will be fine. At least it allows me to sit at my desk, rather than crouching in front of the TV!

ren

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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Fri Jun 08, 2012 4:16 pm

I have just bought the Neweer cable, plugged it in, found the video kept flickering to readjust itself on my Dell U2311H, removed the USB hub which had the mouse/keyboard and it was fine. I managed to get a video setting of mode 16 on DMT.

Luke.

RandomDuck
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Fri Jun 08, 2012 9:10 pm

I bought a similar 1080P HDMI Male to VGA Female converter and it works perfectly with my old Neovo LCD display.

http://www.ebay.co.uk/itm/170850801393s ... 488wt_1163

I thought I would have to manually configure the PI's HDMI port but everything worked automatically. The display is a little 'soft' but is perfectly acceptable and makes good use of an old monitor.

thesynapseuk
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Sat Jun 09, 2012 5:05 pm

I've bought the amazon cable (http://www.amazon.co.uk/gp/product/B007KEIRNG) but I'm having no luck so far.

My RPi boots up with plain HDMI to HDMI - but that leaves me only being able to use it on my massive TV in the living room, when I want to be able to use my RPi with my little 15" VGA screen in the office.

I read around a lot and lot of people recommended the cable above, but I'm having no luck with it.

I've got no other peripherals attached - just trying to get a picture from the Pi at the moment.

Help would be greatly appreciated, otherwise it's going to be difficult to do anything at all with my RPi - and I'm certainly not shelling out over £100 for another HDMI screen for use with a £25 device!

I'm using the Debian Squeeze distro, and config.txt looks like this:

hdmi_drive=1
hdmi_group=1
hdmi_mode=1
hdmi_force_hotplug=1

dom
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Sat Jun 09, 2012 5:21 pm

@thesynapseuk
Do you know what resolutions the VGA monitor supports?

Random things to try:
config_hdmi_boost=4 (or higher)

hdmi_ignore_edid=0xa5000080
(this makes the Pi ignore what is reported in the EDID and so allow driving any mode. Not generally recommended, as display could react badly to unsupported modes.
However the data in the EDID made up by adaptors like this are normally garbage)

hdmi_group=2
hdmi_mode=4

Go through the groups/modes here looking for one that works.
Trouble is the VGA monitor supports a subset of that list, and the adaptor a different subset, and you need to find one they both like
(I'd have guessed group=1, mode=1 VGA was the best chance).

thesynapseuk
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Sat Jun 09, 2012 5:44 pm

Monitor is a LiteView LM15W.
Supports up to 1280x720 (which is what it runs on when it's a second monitor for my Windows laptop).

Will try those things you've suggested and tell you how I do...
Last edited by thesynapseuk on Sat Jun 09, 2012 5:59 pm, edited 1 time in total.

dom
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Sat Jun 09, 2012 5:46 pm

clacktronics wrote:I have been using the amazon neewer one and it works.

Found though with a viewsonic monitor it said it was connected but showed a blank screen.

A trick with it I found was to unplug the VGA connector turn on the pi then plug it back in it tricked it into working. Not useful for everyday use. Must be something to do with an interruption at boot up.
I'd imagine hdmi_ignore_edid=0xa5000080 would have the same effect.

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alexeames
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Sat Jun 09, 2012 6:07 pm

dom wrote:I'd imagine hdmi_ignore_edid=0xa5000080 would have the same effect.
I was about to tell him that, but you got there before me Dom. :roll: :lol:
Alex Eames RasPi.TV, RasP.iO

g4eml
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Wed Jun 13, 2012 8:16 pm

Hi,
I have just bought one of these units from Ebay for £15 from a UK Supplier and it works well on an old VGA LCD Monitor but it needs to be forced into the correct mode in config.txt.
If it is left to auto configure it results in a high scan rate output that my monitor rejected as being out of range. (Looking at the EDID it is probably 1920*1080 which my monitor wouldn't support.)

I ended up with the following settings which gave a good display at 1024*768 resolution.

disable_overscan=1
hdmi_drive=2
hdmi_group=2
hdmi_mode=16

I also had it working in command line at 800*600 using hdmi_mode=9 but couldnt get the Debian LXDE desktop to work at this resolution, it just went blank after typing startx.

It appears to use the Lontium LT8511 Chip which according to the manufacturers website does support audio, although the module as supplied has no audio outputs. Maybe a bit of hacking might bring out the signal.

The chip produces the following EDID when queried using /opt/vc/bin/tvservice. This should give a few modes to try. I haven't tried anything other than DMT 9 and 16.

Code: Select all

Parsing test...
HDMI:EDID version 1.3, 1 extensions, screen size 88x50 cm
HDMI:EDID features - videodef 0xa0 !standby !suspend active off; colour encoding:RGB444|YCbCr422; sRGB is not default colourspace; preferred format is native; does not support GTF
HDMI:EDID ignored unknown descriptor tag 0x0
HDMI:EDID found monitor range descriptor tag 0xfd
HDMI:EDID monitor range offsets: V min=0, V max=0, H min=0, H max=0
HDMI:EDID monitor range: vertical is 50-60 Hz, horizontal is 30-68 kHz, max pixel clock is 150 MHz
HDMI:EDID monitor range does not support GTF
HDMI:EDID found monitor name descriptor tag 0xfc
HDMI:EDID monitor name is LONTIUM
HDMI:EDID found preferred CEA detail timing format: 1920x1080p @ 60 Hz (16)
HDMI:EDID established timing I/II bytes are 21 08 00
HDMI:EDID found DMT format: code 4, 640x480p @ 60 Hz in established timing I/II
HDMI:EDID found DMT format: code 9, 800x600p @ 60 Hz in established timing I/II
HDMI:EDID found DMT format: code 16, 1024x768p @ 60 Hz in established timing I/II
HDMI:EDID standard timings block x 8: 0x6140 A940 0101 0101 0101 0101 0101 0101 
HDMI:EDID found DMT format: code 16, 1024x768p @ 60 Hz (4:3) in standard timing 0
HDMI:EDID found DMT format: code 51, 1600x1200p @ 60 Hz (4:3) in standard timing 1
HDMI:EDID parsing v3 CEA extension 0
HDMI:EDID monitor support - underscan IT formats:yes, basic audio:yes, yuv444:yes, yuv422:yes, #native DTD:1
HDMI:EDID found CEA detail timing format: 720x480p @ 60 Hz (2)
HDMI:EDID found CEA format: code 16, 1920x1080p @ 60Hz 
HDMI:EDID found CEA format: code 31, 1920x1080p @ 50Hz 
HDMI:EDID found CEA format: code 4, 1280x720p @ 60Hz (native)
HDMI:EDID does not understand CEA format code 0
HDMI:EDID does not understand CEA format code 0
HDMI:EDID does not understand CEA format code 0
HDMI:EDID found CEA format: code 2, 720x480p @ 60Hz 
HDMI:EDID does not understand CEA format code 0
HDMI:EDID does not understand CEA format code 0
HDMI:EDID does not understand CEA format code 0
HDMI:EDID does not understand CEA format code 0
HDMI:EDID found audio format 2 channels PCM, sample rate: 32|44|48 kHz, sample size: 16|20|24 bits
HDMI:EDID found Video Capability DB length 2
HDMI:EDID video capability: CE:3 IT:3 PT:0 QS:0
HDMI:EDID found HDMI VSDB length 7
HDMI:EDID HDMI VSDB has physical address 2.0.0.0
HDMI:EDID HDMI VSDB supports AI:yes, dual link DVI:no
HDMI:EDID HDMI VSDB deep colour support - 48-bit:no 36-bit:no 30-bit:no DC_yuv444:no
HDMI:EDID HDMI VSDB max TMDS clock 225 MHz
HDMI:EDID HDMI VSDB has no latency information
HDMI:EDID adding mandatory support for CEA (1) 640x480p @ 60Hz
HDMI:EDID adding mandatory support for CEA (3) 720x480p @ 60Hz
HDMI:EDID adding mandatory support for CEA (17) 720x576p @ 50Hz
HDMI:EDID adding mandatory support for CEA (18) 720x576p @ 50Hz
HDMI:EDID adding mandatory support for CEA (19) 1280x720p @ 50Hz
HDMI:EDID filtering formats with pixel clock > 162 MHz or h. blanking > 1023
HDMI:EDID best score mode is now CEA (1) 640x480p @ 60 Hz with pixel clock 25 MHz (score 136864)
HDMI:EDID best score mode is now CEA (2) 720x480p @ 60 Hz with pixel clock 27 MHz (score 4641472)
HDMI:EDID CEA mode (3) 720x480p @ 60 Hz with pixel clock 27 MHz has a score of 141472
HDMI:EDID CEA mode (4) 1280x720p @ 60 Hz with pixel clock 74 MHz has a score of 265888
HDMI:EDID DMT mode (4) 640x480p @ 60 Hz with pixel clock 25 MHz has a score of 18432
HDMI:EDID DMT mode (9) 800x600p @ 60 Hz with pixel clock 40 MHz has a score of 28800
HDMI:EDID best score mode is now CEA (16) 1920x1080p @ 60 Hz with pixel clock 148 MHz (score 5473248)
HDMI:EDID DMT mode (16) 1024x768p @ 60 Hz with pixel clock 65 MHz has a score of 147185
HDMI:EDID CEA mode (17) 720x576p @ 50 Hz with pixel clock 27 MHz has a score of 141472
HDMI:EDID CEA mode (18) 720x576p @ 50 Hz with pixel clock 27 MHz has a score of 141472
HDMI:EDID CEA mode (19) 1280x720p @ 50 Hz with pixel clock 74 MHz has a score of 192160
HDMI:EDID CEA mode (31) 1920x1080p @ 50 Hz with pixel clock 148 MHz has a score of 307360
HDMI:EDID DMT mode (51) 1600x1200p @ 60 Hz with pixel clock 162 MHz has a score of 215200
HDMI:EDID preferred mode remained as CEA (16) 1920x1080p @ 60 Hz with pixel clock 148 MHz
HDMI:EDID has HDMI support and audio support
edid_parser exited with code 0

In answer to one of the previous questions, it does adjust the VGA output to whatever resolution is presented on the HDMI input. Some experimenting may be necessary to find a mode that your monitor is happy with.

Overall it looks like a good and not to expensive solution to using an old VGA Monitor with the Pi.


Colin

thesynapseuk
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu Jun 14, 2012 8:29 am

Cheers will try these settings.

Where exactly should I put the config.txt file? At the moment it's sitting on the root/top level directory and just contains the text that some of you quote above (haven't tested the last few entries yet - busy this week!).

Is that the right way to do it?

milhouse
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu Jun 14, 2012 8:36 am

thesynapseuk wrote:Cheers will try these settings.

Where exactly should I put the config.txt file? At the moment it's sitting on the root/top level directory and just contains the text that some of you quote above (haven't tested the last few entries yet - busy this week!).

Is that the right way to do it?
Yes.

g4eml
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu Jun 14, 2012 9:07 am

@thesynapseuk
Config.txt must be in the /boot directory and only needs to contain the lines given above.

From your previous post it looks like your monitor and the adaptor might support 1280*720 using the following;

hdmi_group=1
hdmi_mode=4


Colin.

milhouse
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu Jun 14, 2012 9:36 am

@thesynapseuk: To clarify the recent replies which may appear contradictory :)

If you are accessing the SD card from Linux (ie. on the Pi itself), the config.txt file will be in the /boot directory, but if you are accessing the same SD card on a Windows PC the config.txt file will be in the "top level" (root) folder.

thesynapseuk
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu Jun 14, 2012 12:00 pm

Many thanks for the clarification.

I'm accessing the card from a Windows PC so this is important!

thesynapseuk
Posts: 55
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Re: HDMI-VGA Adapter with chip GBP 12, free shipping

Thu Jun 14, 2012 9:07 pm

Unfortunately none of these solutions has helped me.

I can't understand why, having read around and bought a decent cable, I can't get results.

I may have found a solution - a friend of mine has given me a 19" DVI-I monitor (result!) that he happened to have that he wasn't using.

But I'm concerned for the future of the project. If you can't use the Pi with a VGA monitor, that's a major own-goal.

My only other thought is that I have a composite to VGA cable on it's way at the moment, which may remedy things somewhat. I don't really want to admit defeat on this issue. Even if it might be solved for me, it still will remain for a lot of people I would imagine.

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