Links to all my notes (includes mini-projects and source code etc)

Getting VGA from the HDMI socket

On boot up, the Pi HDMI is set to 'half HD' mode (720x1280), which means you can use almost any 'standard' old 'square' (4:3) computer display with a 'VGA' or DVI socket (almost all supported 1024x1280). However driving the display from the Pi HDMI socket requires a converter and this leads to the 'first boot' issue

The /boot/config.txt file is one that's held in the FAT32 partition of the Jessie distro. Since your Windows PC can ';see' the FAT32 files, you can edit config.txt (and cmdline.txt) before booting the Pi. This lets you choose a different HDMI display resolution tot he default (in the event that your display can't cope with half-HD).

Visit www.raspberrypi.org for the full config.txt definition

The First boot issue

A HDMI-VGA converter (or HDMI-DVD adapter) is not be 'seen' by the Pi, so (prior to the 2016 Jessie release) if you didn't have a HDMI display you could use, you had to plug the Pi into an old TV on 'first use' (or plug in an Ethernet adapter, log-into your Router, discover what IP address had been issued to the Pi, 'log in' via PuTTY from your PC) and then edit the Pi system config file (/boot/config.txt) to force HDMI use (hdmi_force_hotplug=1) ...

Cost

A basic 'HDMI to VGA converter' will set you back less than £5 (from eBay) - note you need a 'converter' (from digital HDMI to analogue VGA) and NOT an 'adapter' (which has no conversion circuits inside).

A 'VGA gender changer' (VGA pins to pins) at a cost of about £1 will allow the converter to be plugged directly into a monitor VGA socket eliminating the need for a separate CGA cable although this typically means the Pi has to be more or less mounted onto the back of the monitor to get it close enough to the VGA socket position

Audio output

If you want audio** (from the HDMI) as well, you can expect to pay anything up to £7.50 (you need to be aware that the HDMI socket is only 'specified' to supply 50mA and the Pi's HDMI 'reverse protection' diode D1 is rated at 200mA - if you use a converter with audio 'split-off' it's likely to draw more than this &amp; blow the diode - so make sure you get one tested with the Pi)

**Whilst the GPU will handle H264 video data streams just fine, it seems that the 'surround sound' is another matter, especially as the AC3 / DTS 'licence owners' seem to have no interest in selling the DTS licence needed for 'legal' DTS (surround sound) decode by the GPU.

So whilst you can play movies using the Pi, by default the audio is likely to be 'down-mixed' to stereo, although it IS possible to set 'HDMI audio pass through mode', ie. send the encoded AC3/DTS to the HDMI display (in /boot/config.txt set hdmi_force_edid_audio=1).

Note that the 'default' for HDMI (which is what you will get when you attach a HDMI to VGA converter) is for the 'sender' (Pi) to 'decode' (i.e down mix to stereo) the audio data stream (your cheap HDMI-VGA converter is not going to include a real 5.1 decoder anyway).

In fact, the 'standard' approach seems to be for the GPU to 'down mix to stereo' anything you try to output via the HDMI socket anyway (DRM strikes again), although "current builds" of XBMC (see 1.6) can, apparently, get 6 channel 'pass through' to HDMI = see here, although functions do seem to come and go :-) )