Raspberry pi with commodore 1084S

[Duffydack]

I need some help. I'm trying to hook a Raspberry Pi loaded up with retropie up to my old commodore 1084S. I currently use the monitor with an Amiga 1200 via a rgb scart here.
http://www.ebay.co.uk/itm/320754731999.
I bought a HDMI to scart adaptor thinking I could hook up the Pi and I've been fighting with it since. I get sound but no picture. Does anyone have an idea of how to get this working? Am I better off using composite or maybe VGA adaptor? I know it's possible as seen in this video
https://www.youtube.com/shared?ci=hCdyUUY3Uww
But they don't document their config.

[Stratosplat]

All the information you need is here... http://elinux.org/RPiconfig#Video_mode_options

Try adding hdmi_group=1 to config.txt to enable HDMI TV standard modes, then add the following immediately after...

For progressive SD output, try adding hdmi_mode=2 or hdmi_mode=17 to config.txt for 480p or 576p respectively.

For interlaced SD output, try adding hdmi_mode=6 or hdmi_mode=21 to config.txt for 480i or 576i respectively.

If these lines already exist in config.txt, just edit them with the appropriate values.

If the image is there but not centred, you have the overscan_left=, overscan_right=, overscan_top=, overscan_bottom= options to play with until it is.

This assumes that the monitor supports 480p/i at 60Hz or 576p/i at 50Hz. I'm not familiar with this monitor so can't give any guarantee that it will work.

[Jope]

The 1084 has handy knobs so you can adjust the picture to fill the screen. :-)

[Stratosplat]

Originally Posted by Jope

The 1084 has handy knobs so you can adjust the picture to fill the screen. :-)

Yes, but being able to program the parameters on the Pi has the handy side-effect that you can set up the overscan to match another device you may be using on the same monitor, so once the monitor is tweaked for one, it's tweaked for both.

[Jope]

That is a good point :-)

[Duffydack]

Originally Posted by Stratosplat

All the information you need is here... http://elinux.org/RPiconfig#Video_mode_options

Try adding hdmi_group=1 to config.txt to enable HDMI TV standard modes, then add the following immediately after...

For progressive SD output, try adding hdmi_mode=2 or hdmi_mode=17 to config.txt for 480p or 576p respectively.

For interlaced SD output, try adding hdmi_mode=6 or hdmi_mode=21 to config.txt for 480i or 576i respectively.

If these lines already exist in config.txt, just edit them with the appropriate values.

If the image is there but not centred, you have the overscan_left=, overscan_right=, overscan_top=, overscan_bottom= options to play with until it is.

This assumes that the monitor supports 480p/i at 60Hz or 576p/i at 50Hz. I'm not familiar with this monitor so can't give any guarantee that it will work.

I've tried various hdmi= setups, and even sdtv= configs also.. thanks for the tips tho I will try these and let you know. Would love to get this working. I think the hdmi>scart adapter might be hindering me somehow tho... we'll see.

[Duffydack]

Tried those modes, still no dice. Sound is ok, but video not even a flicker like it's trying to switch. One thing I noticed while pushing the cvbs/rgb button at the back I noticed it showing a faint picture for a nanosecond.... played with it and turns out if it's somewhere between in and out, very very slight tho, it shows the screen fine. I think I'll try get a hdmi to composite lead. Any recommendations on which? I've seen a converter that's powered and one that's straight through.

[demolition]

So is your HDMI to SCART adapter actually outputting an RGB signal? It could just be converting to composite (SCART supports composite as well as s-video and RGB) and then you would just get a black image with that cable since the D9 connector on the monitor is only used for RGB.

[Jope]

.. and composite is fed into the sync signal .. Plausible!

[Amiga1992]

demolition is on to something, it could be so bad that it's just doing what he describes.

[Zeph]

Doubt the hdmi to scart is even looking for an rgb signal, just going for the composite, especially if it's a cheaper one!

[Stratosplat]

Does the HDMI-to-SCART converter run from its own PSU? If it doesn't, there's a limit to how much current the Pi can supply via the HDMI port for running converters. Some exceed this limit.

It is possible to terminally damage some earlier versions of the Pi by trying to pull out-of-spec current levels out of the HDMI port supply pin, so be careful what you plug into one just incase.

[Duffydack]

Originally Posted by demolition

So is your HDMI to SCART adapter actually outputting an RGB signal? It could just be converting to composite (SCART supports composite as well as s-video and RGB) and then you would just get a black image with that cable since the D9 connector on the monitor is only used for RGB.

I've not tried the converter with any other hardware. It was cheap chinese crap, much like the hdmi2av little box I have now, just need to get an av lead (can't believe I don't have one). Only other thing for me to try is hdmi to vga, as there is one on the pi hut site, looks decent, but then I'd need a converter for the monitor to vga too.
Wish the guy on youtube showing it in action would answer me and give me info..

[Duffydack]

Originally Posted by Stratosplat

Does the HDMI-to-SCART converter run from its own PSU? If it doesn't, there's a limit to how much current the Pi can supply via the HDMI port for running converters. Some exceed this limit.

It is possible to terminally damage some earlier versions of the Pi by trying to pull out-of-spec current levels out of the HDMI port supply pin, so be careful what you plug into one just incase.

Powered via usb>microusb, plugged into my Nexus 5 charger..that's the only usb psu I have

[Duffydack]

Success, sort of. The HDMI2AV converter I got with the composite av lead gives me a nearly perfect picture. There's slight interference as you might see here.
https://drive.google.com/open?id=0B_...3NVY0M2dURWUk0
https://drive.google.com/open?id=0B_...ThDcldQNkNnMVE
I tried the hdmi groups, some with better placement and filling screen, others (the interlaced I think) didn't fill screen. The text was a lot harder to read too, so I enabled the sdtv_mode=2 (pal composite) which seems like a more realistic tv output, smaller, less fuzzy text. The interference is worse on the philips monitor I have than the 1084S, so I'll stick to the 1084S as I'd planned. I'm gonna keep playing with it see if I can improve it.. Least I'm getting somewhere now.

[Duffydack]

I'm thinking VGA is the way to go. What are the chances of this "just working"
http://www.ebay.co.uk/itm/390960545955 to convert the monitors DB9 rgb port to vga
http://www.ebay.co.uk/itm/271374214374 to go from hdmi to vga
with a vga cable and a 3.5mm jack to L/R audio out?

[demolition]

That won't work since the 1084S cannot sync to a VGA signal. If you're unlucky, you might even damage the monitor if you try.

This should work, but it is also just composite (CVBS):
http://www.ebay.co.uk/itm/MHL-HDMI-t...cAAOSwMHdXQq0L

[Duffydack]

That's exactly what I got when I tried SCART, which didn't work. This composite way is nearly perfect, apart from the interference lines which are only noticeable on darker/black backgrounds... I'd still like to get rid of them tho. The cheapo converter off ebay might be the culprit. It gets quite warm and comes with a micro usb cable for power but plugging in doesn't do anything, it works the same powered or not (I can't actually tell if its powered on anyway there's no LED). I may try a slightly more expensive hdmi2av box, now I at least getting a picture to work with.
I'm looking at http://www.ebay.co.uk/itm/291880441045 (that name tho!), which boasts "anti-interference"

Cheers.

[Stratosplat]

Originally Posted by Duffydack

I've not tried the converter with any other hardware. It was cheap chinese crap, much like the hdmi2av little box I have now...

Then it's probably outputting composite video which is already natively available from the Pi via the combined AV 3.5mm jack socket. AFAIK, all Pi that don't have a dedicated yellow RCA output jack for composite have this feature.

[Duffydack]

Yes!!! Got it perfect! Got an "Akale" hdmi2av converter (and some extra composite leads just in case) and it's giving me a nice picture with no intereference lines. Just gonna test with different modes (currently 17) see if it's any different/better.
Happy days

http://imgur.com/a/T4yj6

Edit: think I'll stick with mode 21 (576i).