Digital - Analogue Changes on HDMI

iggy1328

So i ran into a issue trying to use a VGA cable on the PI model B Witch my arcade machine is based on.
Couldn't find a easy fix (here or else were)
But ran into this code that forces the pi to output HDMI in non-digital form.
Simply alloying you to use a HDMI-VGA cable instead of the expensive HDMI converters.

This is quoted directly from the site i have found several lines of code on.
"You will also need to make a small change to the config.txt file that Raspberry Pi uses when it boots.
Using a memory card reader on your desktop computer, insert the Raspberry Pi SD card and open config.txt in your preferred text editor.
Look for the following lines:
#hdmi_force_hotplug=1
#hdmi_drive=2
Both options need to be enabled, which you can do by removing the hash symbol and saving. These options enable VGA output through an HDMI adaptor and sets the screen resolution to a low 640 x 480.
If you want a higher resolution Raspberry Pi TV display, remove the hash symbols from the following lines:
#hdmi_group=1
#hdmi_mode= 4
You will also need to edit these two lines, changing hdmi_group to 2 and hdmi_mode to 16. Remember to save your changes before safely removing and replacing in your Raspberry Pi."

Hope this helps others.
Sorry if this is a double post couldn't find this at all here.

=^,^=

Conno123009

Thanks for this! I'm sure it'll be useful for others! :D

iggy1328

Hope so =^,^=

Higgy

I don't think this is going to work. When I first read it I thought #iggy1328 had actually tried it, but re-reading it I don't think you have?

Everywhere I read it says RPi cannot output analogue over HDMI, the Broadcom chip does not have the circuitry.

Anyway, I ordered a normal HDMI (one end) - VGA (the other) cable and have just been trying with the Config.txt I cannot get anything to display on my VGA monitor.

Anyone else had any luck?

mholgatem

@higgy, did you switch to vga mode in your config.txt?

set:
hdmi_group=1
hdmi_mode=1

you may also need to set:
hdmi_force_hotplug=1

The problem with hdmi to vga converters is that they don't usually send the signal back through the hdmi letting the pi know that it is connected and to output via hdmi, so hdmi_force_hotplug should fix that.

mholgatem

You guys can take a look at this wiki page to get more info on config.txt (specifically, about 1/3 of the way down, look for the hdmi_group and hdmi_mode sections for more info)

Higgy

Have I missed something. Reading the original post i thought this was to use a normal Hdmi-vga cable (dumb cable) instead of a hdmi-vga converter.

I use a converter on my single player bartop which has external power from one of the usb's.

I just bought a dumb cable hoping with the right settings I could use that. I will go and have a play with the settings you suggested #mholgatem, but like I said I dont think the Broadcom chip has the ability to output analogue.
The Rpi has been out for quite a while now and there does not seem to be people that are running analogue vga straight from RPi.

I hope I am wrong though.

mholgatem

I just found something that is very relevant. Only use a converter that has an external power supply! On converting hdmi/vga, the display will try to draw current through your hdmi, which can burn out your hdmi. Check out this posting

Higgy

Yeah I read something like that a while ago, I made sure mine has an external PSU (although it comes from RPi USB port!).
Something like the RPi's HDMI port cannot supply enough current.

So far I have had no luck with the VGA, I also broke DVI, so just getting my Config.txt working again and backing it up before more VGA work! ;-)

ian57

@mholgatem thanks for the link, now it is clear.

iggy1328

glad we got some more info on this.
And correct i have not tried this yet as i am awaiting my dumb cables to arrive.

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