RGB to HDMI using a Pi Zero and a small CPLD

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Elminster
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 8:10 am

In the manual it says
In addition, there are two green status LEDs:

the left LED indicates the system is genlocked (flashing indicates genlock has not yet been acquired)
the right LED indicates Mode 7 has been detected, off in Modes 0..6
So surely on the Electron the right led should be off?

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jul 10, 2019 9:27 am

Elminster wrote:
Wed Jul 10, 2019 8:07 am
I though instruction said second led was mode 7 lock, maybe I misread.
Sorry, the left and right designations in the manual are a bit ambiguous, as it obviously depends on which way up you hold the board.

With the later Pi firmware releases that include genlock (20181207_2fdae01 - Early Adopters Release # 4 and later), the LEDs are:
- LED D1: indicates genlock state (off = unlocked, flashing = acquiring, on = locked)
- LED D2: indicates mode 7 (off = modes 0..6, on = mode7)

So if you are geting LED D2 coming on with the Electron, then something is amiss.

Do the menus work at all? Does it work correctly with the Beeb?

Again, I'd recommend trying again with the latest code, and we can take it from there.

Dave
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 3:49 pm

Yes LED D2 is on. Does this on both RGbto HDMI devices. Least I know D2 works, never seen them on before.

Downloaded 2019 code, hmm looks like I am going to have to go backwards on this thread as the config seems to have changed quite a bit.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jul 10, 2019 3:56 pm

Elminster wrote:
Wed Jul 10, 2019 3:49 pm
Downloaded 2019 code, hmm looks like I am going to have to go backwards on this thread as the config seems to have changed quite a bit.
With the latest release, there should never be a need to manually edit the configuration files. Just select the appropriate Profile for the machine and you should get a working setup.

You can then do an auto calibration (hold down SW3), then, once you are happy, select the Save Configuration option and it will be written back to the SD Card. If you want to change any other setiings, then do this through the menus, and again select the Save Configuration option.

The settings for each Profile are held seperartely. If you mess up, then just select Restore Configuation, and the original settings for the currently selected Profile will be restored.

Once you get used to this, it works very nicely, and is very quick to get setup.

(IanB did most of this work, so you have him to thank)

Dave
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 4:56 pm

It sounds much like black magic. Will give the Harry Potter version a go.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 5:30 pm

Issue 1 fixed. Issue with software caused by mac putting a weird mapping, changed it to mbr and now boots.

Picture not as good as original software, but not updated CPLD yet, or possibly I need to tweak the settings more.

Edit: I thought I had installed latst CPLD, I hadnt twigged I had installed latest in Master, not as recommend from Dev.
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jul 10, 2019 5:47 pm

Elminster wrote:
Wed Jul 10, 2019 5:30 pm
Picture not as good as original software, but not updated CPLD yet, or possibly I need to tweak the settings more.
How would you describe the degradation?

What CPLD version are you currently running? (The Info menu will tell you this)

Do update the CPLD to 6.4, as there were some changes that affect picture quality.

There is a issue in github relating to picture quality:
https://github.com/hoglet67/RGBtoHDMI/issues/62

If you still feel the picture is not as good after updating the CPLD, it would be good to compare the calibration results between the different software versions.

In fact, that might really help, as what's prevented me closing this issue out is really lack of data.

Dave
Last edited by hoglet on Wed Jul 10, 2019 5:48 pm, edited 3 times in total.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 6:10 pm

hoglet wrote:
Wed Jul 10, 2019 5:47 pm
Elminster wrote:
Wed Jul 10, 2019 5:30 pm
Picture not as good as original software, but not updated CPLD yet, or possibly I need to tweak the settings more.
How would you describe the degradation?

What CPLD version are you currently running? (The Info menu will tell you this)

Do update the CPLD to 6.4, as there were some changes that affect picture quality.

There is a issue in github relating to picture quality:
https://github.com/hoglet67/RGBtoHDMI/issues/62

If you still feel the picture is not as good after updating the CPLD, it would be good to compare the calibration results between the different software versions.

In fact, that might really help, as what's prevented me closing this issue out is really lack of data.

Dave
The Master head which is 2.1 I think. I have the dev version downloaded. I could use the new screenshot function, I am assuming it gets saved to the sdcard.

But as far as I can see I have put the setting correctly. i.e. resolution as before and 'Electron' and I have a 5 cm border on the left, 2cm border on the top. And the text jitters, on the old version I used to set elk=1 and mux=1 to fix that. Assumed that was done automatically by setting profile to 'Electron'

Info screen reports 'Normal CPLD 2.1' Pi Firmware is 20198518 49328d4' (I think, text is a bit fuzzy).

Not played with any of the other settings.

The calibration summary has 'Clk Err 471 ppm (source slower than Pi)' So guessing the calibration is wrong, hence the jitter. I could try new pi firmware on original CPLD code now that is working.

Edit: Forgot to say the HDMI auto-calibrate button fails with Genlock error.
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 6:17 pm

In the interest of science, I tried 2019 firmware on my other RGB with CPLDv1.0 and that is completely unreadable.

Next stop flash one of them with CPLD 6.4, probably the one with 2.1

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jul 10, 2019 6:28 pm

OK, so to avoid confusion, lets focus on one machine at at time.

So lets start with the Electron.

The github issue I just metioned only affects Mode 7, so something else is going wrong here.
Elminster wrote:
Wed Jul 10, 2019 6:10 pm
But as far as I can see I have put the setting correctly. i.e. resolution as before and 'Electron' and I have a 5 cm border on the left, 2cm border on the top. And the text jitters, on the old version I used to set elk=1 and mux=1 to fix that. Assumed that was done automatically by setting profile to 'Electron'
Make sure the Profile is set to Electron.

The default Resolution (for the the system as a whole), is Auto. This is whatever the Pi Firmware decides to choose as "best" from the EDID data your monitor advertises. It's probabaly 60Hz, so needs changing. In the top menu, select the Resolution you want (the same as your monitor), and make sure it's @50Hz. Once you exit the menu, the system will automatically reboot to the new resolution.
Elminster wrote:
Wed Jul 10, 2019 6:10 pm
Info screen reports 'Normal CPLD 2.1' Pi Firmware is 20198518 49328d4' (I think, text is a bit fuzzy).
If the screen is shifted horizontally, that's something that will be fixed I think if you upgrade to the 6.4 CPLD.
Elminster wrote:
Wed Jul 10, 2019 6:10 pm
The calibration summary has 'Clk Err 471 ppm (source slower than Pi)' So guessing the calibration is wrong, hence the jitter. I could try new pi firmware on original CPLD code now that is working.
The clock difference (in ppm) is actally irrelevant, as long as it's < ~1000ppm. Values of ~500 are very typical, and just reflect the difference in clocks. This is all taken into account.
Elminster wrote:
Wed Jul 10, 2019 6:10 pm
Edit: Forgot to say the HDMI auto-calibrate button fails with Genlock error.
This suggests the resolution/refresh rate is 60Hz rather the 50Hz.

Also, note:
- a short press of SW3 gives HDMI Calibration (==Genlock)
- a long press of SW3 gives Auto Calibration

Also, is the LD2 (Mode 7) still coming on? If it is, then that would explain why the picture is crap.

BTW, it's great to work through this, because I want to write a Quick Start guide for the new software, and this will really help.

Dave
Last edited by hoglet on Wed Jul 10, 2019 6:32 pm, edited 3 times in total.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jul 10, 2019 6:49 pm

I've just tested the latest Pi Software against CPLD 2.1 and the Elk.

It really does look dreadful!

This is because the Auto Calibration is not calculating the pixel delay correctly, and ends up picking the worst possible sample position. It can be manually corrected, but there's little point.

Updaing to the CPLD 6.4 Firmware fixes everything on my system.

Ian and I talked alot about how much effort we wanted to put into supporting older firmware versions with the new Pi software. The conclusion was, given there are only ~10 units out there with old firmware, that it was better just to encourage people to update to 6.4.

Dave
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 7:00 pm

Right ho thanks. Upgrading the cpld is a job for this evening hopefully.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 9:32 pm

Okay CPLD 6.4 is in and the picture is as crisp, maybe better than my v1.0 RGBHDMI, so that is issue 2 sorted.

Only issue I have now is even with it set to 'Electron' the screen resolution I used to use (or set to auto). The whole thing is offset. Tried auto-calibrate but that didn't shift it. Will upload a picture later. But basically, the left margin in 5-10 cms, and the top margin is around 3cms.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Wed Jul 10, 2019 9:51 pm

Clearly weird stuff happening with the resolution. If I put the v1.0 RGBHDMI back in, supposedly running at the same resolution it fills the whole screen, and all the text is much chunkier.

I am using same HDMI cable and same RGB to Electron cable (which is a pain to keep swapping, need to make another one), and obviously to the same screen.

With CPLD v1.0 + Firmware 20180718 695249b fills whole screen

With CPLD 6.4 + Firmware 2019 get the cut-down picture

With CPLD 6.4 + Firmware 20180718 695249b also gets cut down picture (although you have to switch it to all offset 0) but the border at the top is gone, just the border on the edge.

Had a quick fiddle with the offsets but so far no difference.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Wed Jul 10, 2019 9:53 pm

Elminster wrote:
Wed Jul 10, 2019 9:32 pm
Only issue I have now is even with it set to 'Electron' the screen resolution I used to use (or set to auto). The whole thing is offset. Tried auto-calibrate but that didn't shift it. Will upload a picture later. But basically, the left margin in 5-10 cms, and the top margin is around 3cms.
It might be helpful to temporarily set a border color (in preferences).

Then can you take a photo, rather than use screen shot, so I can see the whole screen including the borders?

Without being able to see this, it's really hard to help!

What''s the monitor you are using, and what resolution are you using?

Dave
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Thu Jul 11, 2019 8:44 pm

I had already done the screenshots, I just hand not uploaded them. I didn't have a colour border but I did use characters to set the border.

Same monitor I used at the start of this thread, will find the post in a second. Now if I can remember which one is which.

1. Original RGB with v1.0 CPLD & older 2018 Firmware
IMG_5053.png
2. New CPLD 6.4 with older 2018 Firmware (boarder on left)
IMG_5054.png
3. New CPLD 6.4 with 2019 Dev firmware (extra boarder on top)
IMG_5057.png
4. As 3, No colour but showing screen display size
IMG_5058.png
Edit: Link to original monitor post viewtopic.php?f=3&t=14430&start=210#p209299 although wont help much.
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Thu Jul 11, 2019 8:47 pm

Duncan,

Can you try the following:
- In the preferences menu, set the border colour to red (1)
- On the electron, type VDU 19,0,4;0;

Then take another photo.

Then we can see a bit more clearly what's going wrong.

Also, what resolution are you running at?

Dave
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Thu Jul 11, 2019 8:51 pm

I have always run it ## 720x576 @ 50Hz but have set it to auto as well but behaves the same.

But it actually does 720p @ 60 hz according to the monitor when using CPLD 6.4, need to go check if that was what it was doing on CPLD 1.0

The photo is out of focus the picture is actually quite sharp.

Edit: Will do the photo shortly, it is a pain as my photos seem to no longer sync with my PC, for reasons I haven't got to the bottom of yet.

Edit2: Okay that is weird. CPLD 1.0 is running at 576p 50Hz, which I believe is 720x576
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Thu Jul 11, 2019 9:12 pm

Elminster wrote:
Thu Jul 11, 2019 8:51 pm
But it actually does 720p @ 60 hz according to the monitor when using CPLD 6.4, need to go check if that was what it was doing on CPLD 1.0
This is wierd, as I've just tested this configuration on my 800x600 monitor and it looks fine:
IMG_1708.JPG
The only thing I changes was:
- Profile (to Electron)
- Resolution (to 800x600@50Hz)
- Interpolation (to Medium)
- then exit menu to allow for reboot
- Settings/Font SIze to make the menu font a bit larger so you can read it

If you want, you can get rid of the top/bottom red borders by changing the Preference/Scaling (to Non-Integer):
IMG_1709.JPG
If your monitor is reporting 720p when you set 800x600, then that's something we need to look at before messing with anything else. Maybe your monitor doesn't like 800x600@50Hz, in which case try 720x576@50Hz.

Dave
Last edited by hoglet on Thu Jul 11, 2019 9:21 pm, edited 3 times in total.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by IanB » Thu Jul 11, 2019 9:13 pm

Elminster wrote:
Thu Jul 11, 2019 8:44 pm
I had already done the screenshots, I just hand not uploaded them. I didn't have a colour border but I did use characters to set the border.
That looks like a 1280x1024 monitor and you can't do full integer scaling (which is the default) with that resolution although there is a slightly later build which will support integer scaling in 1280x1024 with a few pixels cropped off the right hand edge in some modes. This is because the video capture area has to be slightly larger than 640x256 to capture all modes so it won't integer scale to 1280x1024.

To get the same result as previously, change the scaling from "Integer" to "Fill 4:3" or "Fill All" and then save configuration.
After that the image will fill the screen but be ragged due to non-integer scaling so you have to switch on interpolation as well so change that from off to medium. This will prompt for a reboot and after that it should be equivalent the previous version.

If you want to experiment with integer scaling you can try the slightly updated version here (wipe the SD card before unzipping the contents):
https://github.com/IanSB/Testfiles
As mentioned this will crop a few pixels in integer mode but at least it will fill the screen unlike the version you are testing.
You can still use the "Fill 4:3" etc method with this version but you should be able to see the difference between integer and non-integer scaling.

Integer scaling is only really suitable for 1920x1080, 1920x1200 and 1600x1200 monitors although I intend in future to see if I can auto adjust the horizontal position of the capture area in 1280x1024 following each mode change so that it would avoid the few cropped pixels.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Thu Jul 11, 2019 9:19 pm

IanB wrote:
Thu Jul 11, 2019 9:13 pm
That looks like a 1280x1024 monitor and you can't do full integer scaling (which is the default) with that resolution although there is a slightly later build which will support integer scaling in 1280x1024 with a few pixels cropped off the right hand edge in some modes. This is because the video capture area has to be slightly larger than 640x256 to capture all modes so it won't integer scale to 1280x1024.
Ian, I believe its's an 800x600 native resoution monitor:
https://www.ebay.co.uk/itm/ZOTER-12-Inc ... SwmgJY5eIf

So Integer scaling should give reasonable results, don't you agree?

I'd rather not throw in another variable of another Pi Software version unless it's really necessary, which I don't think it is in this case.
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Thu Jul 11, 2019 9:29 pm

While fiddling I switched it back to auto resolution. Auto seems to get the wrong resolution in CPLD 6.4, works okay in CPLD 1.0

So yes with resolution forced to 720x576@50 and scaling set to integer it is back to before in 6.4

But I am interested that the monitor does seem to do 720p which I had realised it would do. So I could test the new version.

Edit: Test it by putting back to auto and it goes into 720p mode again
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Thu Jul 11, 2019 9:38 pm

Elminster wrote:
Thu Jul 11, 2019 9:29 pm
Edit: Test it by putting back to auto and it goes into 720p mode again
That's expected. Even though your monitor's native resolution is 800x600, it likely supports 1280x720 over HDMI (so it could claim to be HD Ready). When set to Resolution=Auto, the Pi will pick the highest resolution. This won't look great, because the monitor's cheap scaler will come into play. Also, the (4:3) monitor will assume the signal is widesceen (16:9) aspect ratio, hence the large borders at the top/bottom.

(The reason I was asking you to set the red background was so I could see whether the monitor was also distoring the image, which it seems it was).

I would strongly suggest setting Resolution to 800x600@50Hz or 720x576@50Hz, then play around with the Preferences/Scaling setting.

Dave
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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by IanB » Thu Jul 11, 2019 9:53 pm

hoglet wrote:
Thu Jul 11, 2019 9:19 pm
Ian, I believe its's an 800x600 native resoution monitor:
Sorry I wrote my reply while the monitor info was being posted so missed it.
hoglet wrote:
Thu Jul 11, 2019 9:19 pm
So Integer scaling should give reasonable results, don't you agree?
It should if it is actually 800x600 but not if it's 1024x 768 or 1280 x1024 when I would expect the above "postage stamp" results.

I have seen other 4:3 monitors listed as both 800x600 and 1024x768 under the same model designation with a slight difference in price and maybe a different suffix on the model number so the above link might not be definitive.

As a general rule, if you are getting this sort of postage stamp effect and the output resolution is set correctly, it means the integer scaling is non-optimal and the only option is to switch on Fill 4:3 / All and enable interpolation.

I notice we haven't included any 1024x768 modes so that needs to be addressed as well as some 60Hz versions of the 50Hz modes.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Thu Jul 11, 2019 9:59 pm

I am happy it now looks as good as original cpld 1.0, maybe better, hard to say.

I may look at 800x600 or even if at a later date 1024x768 etc. But this was one I had just built so wanted just make sure I could get a good a picture as the original. Which I can. So for now that is all my issues sorted.

Thanks. All.

Next project is to do some more cables and fit in project boxes. But have some other soldering to do first. On a solder binge of getting all the boards, some I have had for years, finished.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by BigEd » Thu Jul 11, 2019 10:03 pm

(Is there, say, a Basic one-liner to plot a Moiré carpet, to try to show up how sharp things are?)

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by hoglet » Thu Jul 11, 2019 10:10 pm

Elminster wrote:
Thu Jul 11, 2019 9:59 pm
I am happy it now looks as good as original cpld 1.0, maybe better, hard to say.
For the benefit of the forthcoming quick start guide, can you summarise what you ended up changing please?

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by IanB » Thu Jul 11, 2019 10:27 pm

hoglet wrote:
Thu Jul 11, 2019 9:38 pm
That's expected. Even though your monitor's native resolution is 800x600, it likely supports 1280x720 over HDMI (so it could claim to be HD Ready). When set to Resolution=Auto, the Pi will pick the highest resolution.
That seems to be the case here and it's rather annoying as you can't determine the actual physical resolution of the monitor from the auto setting.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Thu Jul 11, 2019 10:38 pm

hoglet wrote:
Thu Jul 11, 2019 10:10 pm
Elminster wrote:
Thu Jul 11, 2019 9:59 pm
I am happy it now looks as good as original cpld 1.0, maybe better, hard to say.
For the benefit of the forthcoming quick start guide, can you summarise what you ended up changing please?
Issue 1 - Reformating a Unix sdcard on a Mac can leave you with extra mapping partitions that screws pi from booting. Manually removed with Fdisk.
Issue 2a - Put on cpld from master instead of dev branch
Issue 2b used latest stable firmware, dev firmware works better on Electron
Issue 3 - auto resolution seemingly picks wrong resolution

Think that was all.

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Re: RGB to HDMI using a Pi Zero and a small CPLD

Post by Elminster » Fri Jul 12, 2019 1:51 pm

One other thought, you could add instructions on wiring the cable (unless I missed it). Even if it was just a link to the Electron/Beeb RGB pinout. I just makes it easier if all the instructions are in one place, rather than bouncing between pages.

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